FINAL REPORT APMP-APLAC Joint Proficiency Testing ...

APMP-APLAC Joint Proficiency Testing Programme

(APLAC T107)

Elements in Food Supplement

FINAL REPORT


(APLAC T107)


Organized by

Government Laboratory of Hong Kong (GLHK)

September 2018


(APLAC T107)


Page 1 of 108

Content

Summary ……………………………………………………………………………............................... 3

1. Introduction ……………………………………………………………………............................... 5

2. Objectives …………………………………………………………………………......................... 6

3. Proficiency test sample …………………………………………………………….......................... 6

4. Reporting and submission of results ……………………………………………………………..... 7

5. Evaluation of performance of participants ………………………………………………………… 8

6. Results and discussions …………………………………………………………….......................... 9

7. Recommendations ……………………………………………………………................................. 19

8. Acknowledgements and remarks …………………………………………….................................. 19

9. References ……………………………………………………………………................................. 20

TABLE I. Programme schedule ……………………………………………………............................... 21

TABLE II. Geographical distribution of participants ………………………………….......................... 22

TABLE III. Participants’ results and the z-scores for zinc ……………………………………………… 23

TABLE IV. Participants’ results and the z-scores for manganese …………………............................... 26

TABLE V. Participants’ results and the z-scores for calcium ………………………………………… 29

TABLE VI. Participants’ results and the z-scores for magnesium ………………................................... 32

TABLE VII. Technical information – methods of analysis of zinc ………………................................. 35

TABLE VIII. Technical information – methods of analysis of manganese ………................................. 39

TABLE IX. Technical information – methods of analysis of calcium ………………............................ 43

TABLE X. Technical information – methods of analysis of magnesium ……………………………… 47

TABLE XI. Participants’ results and the zeta-scores for zinc ………………………………………….. 51

TABLE XII. Participants’ results and the zeta-scores for manganese …………………………………. 53

TABLE XIII. Participants’ results and the zeta-scores for calcium …………………........................... 55

TABLE XIV. Participants’ results and the zeta-scores for magnesium ……………….......................... 57

FIGURE I. Participants’ z-scores for zinc …………………………………………............................... 59

FIGURE II. Participants’ z-scores for manganese …………………………………............................... 60

FIGURE III. Participants’ z-scores for calcium ……………………………………………………..... 61

FIGURE IV. Participants’ z-scores for magnesium …………………………………............................. 62

FIGURE V. Participants’ results with their expanded uncertainty for zinc ………................................. 63

FIGURE VI. Participants’ results with their expanded uncertainty for manganese ……......................... 64

FIGURE VII. Participants’ results with their expanded uncertainty for calcium …………………..... 65

FIGURE VIII. Participants’ results with their expanded uncertainty for magnesium ………………..... 66


(APLAC T107)


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FIGURE IX. Participants’ zeta-scores for zinc ……………………………………………………….... 67

FIGURE X. Participants’ zeta-scores for manganese ………………………………….......................... 68

FIGURE XI. Participants’ zeta-scores for calcium …………………………………............................. 69

FIGURE XII. Participants’ zeta-scores for magnesium ……………………………………………….. 70

FIGURE XIII. Kernel density plot of zinc …………………………………………............................... 71

FIGURE XIV. Kernel density plot of manganese ……………………………………………………... 72

FIGURE XV. Kernel density plot of calcium …………………………………………........................ 73

FIGURE XVI. Kernel density plot of magnesium …………………………………............................... 74

FIGURE XVII. Participants’ results with respect to the digestion techniques for zinc ……………….. 75

FIGURE XVIII. Participants’ results with respect to the digestion techniques for manganese ……….. 76

FIGURE XIX. Participants’ results with respect to the digestion techniques for calcium …………….. 77

FIGURE XX. Participants’ results with respect to the digestion techniques for magnesium ………..... 78

FIGURE XXI. Participants’ results with respect to the use of internal standard(s) for zinc ………..... 79

FIGURE XXII. Participants’ results with respect to the use of internal standard(s) for manganese …… 80

FIGURE XXIII. Participants’ results with respect to the use of internal standard(s) for calcium …….. 81

FIGURE XXIV. Participants’ results with respect to the use of internal standard(s) for magnesium …. 82

FIGURE XXV. Participants’ results with respect to the analytical instruments for zinc ……………… 83

FIGURE XXVI. Participants’ results with respect to the analytical instruments for manganese ……… 84

FIGURE XXVII. Participants’ results with respect to the analytical instruments for calcium ………... 85

FIGURE XXVIII. Participants’ results with respect to the analytical instruments for magnesium …… 86

FIGURE XXIX. Participants’ results with respect to the correction for recovery for zinc …………… 87

FIGURE XXX. Participants’ results with respect to the correction for recovery for manganese …...... 88

FIGURE XXXI. Participants’ results with respect to the correction for recovery for calcium ………... 89

FIGURE XXXII. Participants’ results with respect to the correction for recovery for magnesium …… 90

FIGURE XXXIII. Participants’ results with respect to the method accreditation status for zinc …….. 91

FIGURE XXXIV. Participants’ results with respect to the method accreditation status for manganese . 92

FIGURE XXXV. Participants’ results with respect to the method accreditation status for calcium …. 93

FIGURE XXXVI. Participants’ results with respect to the method accreditation status for magnesium . 94

APPENDIX I. Homogeneity study …………………………………………………............................... 95

APPENDIX II. Stability study ………………………………………………………………………… 96

APPENDIX III. Instructions for Participants ………………………………………………………….. 97

APPENDIX IV. Sample Receipt Form ………………………………………………………………… 103

APPENDIX V. Results Proforma ……………………………………………………………………... 104


(APLAC T107)


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Summary

1. This APMP-APLAC joint proficiency testing programme (APLAC T107) was

organized by the Government Laboratory of Hong Kong (GLHK) under the

auspices of the Asia-Pacific Metrology Programme (APMP) - Asia Pacific

Laboratory Accreditation Cooperation (APLAC) Joint Proficiency Testing

Working Group (PTWG). The purposes of the study are (i) to assist participating

laboratories to demonstrate their capabilities in determining the mass fractions of

four analytes (zinc, manganese, calcium and magnesium) at mg/kg levels in a test

sample of food supplement by various analytical techniques; and (ii) to identify

areas for improvement.

2. A total of 53 laboratories from 18 economies enrolled in the PT programme and 52

of them returned the Result Proforma to GLHK within the scheduled timeline.

3. The programme was concurrently conducted in parallel with the APMP

Supplementary Comparison “Elements in Food Supplement” APMP.QM-S10

using the same test material. It was stipulated in the proposal for the PT programme

that the supplementary comparison reference values (SCRVs) obtained from

APMP.QM-S10, which had participation from national metrology institutes

(NMIs) and designated institutes (DIs) worldwide, were to be used as the assigned

values for evaluating the performance of participants in the APLAC T107. The

standard deviation for proficiency assessment was derived from the Horwitz

Equation [9.1]. The z-scores were used to show the performance of participants

with respect to the assigned values of the analytes of interest.

4. Participants’ z-scores on the four analytes are summarized as follows:

z-Score

Number of Participants (Percentage)

Zinc Manganese Calcium Magnesium

z 2.0 30 (61%) 31 (66%) 20 (43%) 27 (59%)

2.0 < z < 3.0 7 (14%) 7 (15%) 10 (21%) 5 (11%)

z 3.0 12 (24%) 9 (19%) 17 (36%) 14 (30%)

Total: 49 (100%) 47 (100%) 47 (100%) 46 (100%)


(APLAC T107)


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5. To allow participants to check for transcription errors, an Interim Report of APLAC

T107 was issued in June 2017. The proposed SCRVs for zinc, manganese, calcium

and magnesium were discussed at the meetings of the Inorganic Analysis Working

Group (IAWG) of the Consultative Committee for Amount of Substance:

Metrology in Chemistry and Biology (CCQM) in April and September 2017, and

were approved by the CCQM IAWG in April 2018 [9.2]. As it was agreed that the

SCRVs of APMP.QM-S10 would be used as the assigned values for performance

evaluation, confirmation of these values was required prior to issue of this Final

Report on APLAC T107. This Final Report gives a comprehensive overview of

participants’ results and detailed discussions on methods of analysis used by

participants.


(APLAC T107)


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1. Introduction

1.1. CODEX Alimentarius establishes the guidelines that apply to vitamin and mineral

food supplements intended for use in supplementing the daily diet with vitamins

and/or minerals [9.3]. Mineral food supplements are commercially available and

marketed in forms of tablets, capsules, powders, solutions, etc. In cases where the

intake from the diet is insufficient or where consumers consider their diet requires

supplementation, mineral food supplements are often consumed to supplement the

daily diet. The amounts of the minerals should be properly declared in the labelling

of the products. The use of reliable methods for measurement of minerals is

important in safeguarding the quality of these products and the public health.

1.2. With the aim of enhancing the quality and traceability of measurements in various

economies of the Asia-Pacific region through a better regional scientific

infrastructure, the APMP and the APLAC agreed to strengthen cooperation. At the

APMP General Assembly and Related Meetings held in Taipei in November 2013,

both APMP and APLAC agreed to establish the APMP-APLAC Joint PTWG as a

formal infrastructure to provide more proficiency testing programmes with

metrologically traceable reference values for performance evaluation. To echo this

new initiative, APLAC T107 was organized by the GLHK under the auspices of

the APMP-APLAC Joint PTWG.

1.3. The APLAC T107 was concurrently conducted in parallel with the supplementary

comparison APMP.QM-S10 “Elements in Food Supplement” using the same test

material. It was stipulated in the Instructions for Participants for the PT programme

that the SCRVs obtained from APMP.QM-S10 would be used as the assigned

values for evaluating the performance of participants in the APLAC T107. The

standard deviation for proficiency assessment would be derived from the Horwitz

Equation [9.1].

1.4. GLHK took responsibility for preparation and distribution of proficiency test

samples, provision of APMP.QM-S10 SCRVs for performance evaluation and data

analysis, preparation of interim and final reports, and communications with

participants.

1.5. A total of 53 laboratories from 18 economies enrolled in the PT programme and 52

of them returned the Result Proforma on or before the final deadline of 31 March

2017 (TABLE II). Each participant was assigned with a unique laboratory code and

the code was used throughout the PT programme for identification purposes. For

the determination of zinc, manganese, calcium and magnesium, 49, 47, 47 and 46

laboratories submitted their results before the deadline respectively.


(APLAC T107)


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2. Objectives

2.1. The PT programme targets the analysis of four elements (zinc, manganese, calcium

and magnesium) in a test sample of food supplement. The purposes of the study are

(i) to assist participating laboratories to demonstrate their capabilities in

determining the mass fractions of four analytes (zinc, manganese, calcium and

magnesium) at mg/kg levels in a test sample of food supplement by various

analytical techniques; and (ii) to identify areas for improvement. The mass fractions

of the analytes on dry-mass basis are used for comparability purposes.

2.2. Participants’ results were processed in accordance with the statistical techniques

outlined in ISO 13528:2015 [9.4].

3. Proficiency test sample

3.1. About 20 kg of food supplement tablets was purchased from the local market.

Preliminary analysis of the food supplement tablets has been conducted to check

the levels of the target analytes. The food supplement tablets were blended to give

a powder. The powder was subjected to a sieving process through two calibrated

sieves (200 and 100 µm respectively). The sieved powder (particle sizes: 100 – 200

µm) was thoroughly homogenised in a 3-dimensional mixer for 5 days. The

material was irradiated using a gamma source at a dose of about 1 kGy for

disinfection. The irradiated material was packed into pre-cleaned and nitrogen-

flushed high density polyethylene bottles then each bottle vacuum-sealed in a

polypropylene bag. About 250 bottles each containing about 25 g of sample were

prepared. All prepared bottles of sample are stored at room temperature (20 ± 5C)

prior to distribution or use.

3.2. Homogeneity and stability studies of the test material were carried out in

accordance with the procedures stipulated in APPENDICES I and II. The results

indicated the test material was sufficiently homogeneous and adequately stable for

use in the proficiency testing programme.

3.3. Each registered participant was provided with one sample bottle containing about

25 g of food supplement powder, which was distributed by courier service in

January 2017. Relevant documents including “Instructions for Participants”,

“Sample Receipt Form” and “Result Proforma” were sent via e-mails

([email protected]) to the registered participating laboratories at

the time of distribution of the proficiency test samples. Specimen copies of these

documents are provided in APPENDICES III to V. The range of values for the

proficiency test sample is as follows:

mailto:[email protected]


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Measurand Mass fraction (expected range of values)

Zinc 1000 – 20000 mg/kg

Manganese 1000 – 10000 mg/kg

Calcium 10000 – 200000 mg/kg

Magnesium 10000 – 100000 mg/kg

3.4. Upon receipt of the proficiency test samples, participants were requested to

immediately check the physical conditions of the bottles and promptly return the

“Sample Receipt Form” via e-mails ([email protected]) to

GLHK for confirmation of receipt of samples. Replacement would be arranged if

the proficiency test sample was identified to be not suitable for analysis. GLHK did

not receive any complaints in respect of loss/damage of samples.

4. Reporting and submission of results

4.1. Participants were required to complete the Results Proforma (APPENDIX V) and

to report test results in the following manner:

(a) Units of measurement: Report the mass fractions of the analytes and associated

uncertainties in mg/kg;

(b) Number of significant figures: Report the test results to 3 significant figures;

(c) Reporting basis: Report the test results on “dry-mass basis”;

(d) For each analyte, the mean value of at least three independent measurements,

the expanded uncertainty of the mean value and the coverage factor (which

gives a level of confidence of approximately 95 %) should be reported;

(e) Participants should provide information on the methods of analysis; and

(f) For the determination of dry mass correction, a minimum of three separate

portions (recommended size to be about 1 g each) of the sample shall be taken

and placed over anhydrous calcium sulphate (DRIERITE) in a desiccator at

room temperature for a minimum of 20 days until a constant mass is reached.

Dry mass correction shall be carried out at the same time as the test sample

portions are to be analysed.



(APLAC T107)


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5. Evaluation of performance of participants

5.1. Performance evaluation

5.1.1. Participants’ performance was assessed using a numeric indicator, z-score,

which is calculated as follows:

z𝑖 =x𝑖 − x𝑝𝑡

σ𝑝𝑡

where xi : the participant’s result

xpt : the assigned value*

pt : the standard deviation for proficiency assessment

estimated from the Horwitz equation [σpt =

0.02c0.8495, where c is the assigned value of the

analyte expressed as a dimensionless mass ratio (e.g.

1 mg/kg = 1 ppm = 10-6) [9.1, 9.4]

* Note: The SCRVs obtained from APMP.QM-S10 were used as the

assigned values for evaluating the performance of participants. This is in

accordance with the ISO/IEC 17043 recommendations on the determination

of assigned values for proficiency testing schemes [9.5].

5.1.2. The z-score is commonly interpreted as (a) z 2.0 Satisfactory (b) 2.0 < z < 3.0 Questionable (c) z 3.0 Unsatisfactory

5.1.3. Participants having z 3.0 should thoroughly investigate their results.

Participants having z-scores in the range 2.0 < z < 3.0 are also encouraged

to review their results.

5.2. Participants were informed in the Instructions for Participants for APLAC T107

that the SCRVs obtained from APMP.QM-S10 would be used as the assigned

values for evaluating the performance of participating laboratories and that the

standard deviations for proficiency assessment would be derived from the Horwitz

equation.


(APLAC T107)


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5.3. For reference purpose, the performance of the participating laboratories was

assessed using zeta-score (), which is calculated as follows:

𝑖

=x𝑖 − x𝑝𝑡

√𝑢2(x𝑖) + 𝑢2(x𝑝𝑡)

where xi : the participant’s result

xpt : the assigned value

u(xi) : the participant’s own estimate of the standard

uncertainty of its result xi.

u(xpt) : the standard uncertainty of the assigned value xpt

-scores are interpreted as in the same way as z-scores using the same critical values

of 2.0 and 3.0. -scores may be used in conjunction with z-scores, as an aid for

improving the performance of laboratories as follows. If a laboratory obtains |z|

scores that exceed 3.0, they may find it of value to examine their test procedure step

by step and derive an uncertainty budget for that procedure. The uncertainty budget

will identify the steps in the procedure where the largest uncertainties arise, so that

the laboratory can see where to expend effort to achieve an improvement. If their

|| scores also exceed the critical value of 3.0, it implies that their uncertainty budget

does not include all significant sources of uncertainty [9.4]. Laboratories are

encouraged to review their uncertainty budget.

5.4. To allow participants to check any transcription errors, an Interim Report of

APLAC T107 was issued in June 2017. The proposed SCRV for zinc, manganese,

calcium and magnesium were discussed at the CCQM IAWG Meetings in April

and September 2017 and were approved by the CCQM IAWG in April 2018 [9.2],

and this Final Report on APLAC T107 is issued upon confirmation of the SCRVs

of APMP.QM-S10 that would be used as the assigned values for performance

evaluation for APLAC T107. This Final Report gives a comprehensive overview

of participants’ results and detailed discussions on methods of analysis used by

participants.

6. Results and discussions

6.1. Participants’ results including reported result, combined standard uncertainty,

coverage factor, expanded uncertainty, z-scores and method accreditation status for

zinc, manganese, calcium and magnesium are given in TABLES III to VI

respectively and presented graphically in FIGURES I to VIII. Laboratory numbers

1 – 4 represent the laboratories that were nominated by the APMP Developing

Economies’ Committee (APMP DEC), whereas laboratory numbers 5 – 54


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represent the laboratories that were nominated by the APLAC accreditation bodies

and non-APLAC accreditation bodies.

6.2. Assigned values for evaluation of the performance of participants

6.2.1. The SCRVs of APMP.QM-S10 were used as the assigned values for

evaluation of the performance of participants. This was in line with the

ISO/IEC 17043 recommendations on the determination of assigned values

for proficiency testing schemes [9.5]. For APMP.QM-S10, a total of 14

institutes (NMIs/DIs) participated in the supplementary comparison. A

variety of instrumental techniques including inductively coupled plasmas

mass spectrometry (ICP-MS), inductively coupled plasmas optical emission

spectrometry (ICP-OES), flame atomic absorption spectrometry (FAAS),

and instrumental neutron action analysis (INAA) were employed by the

participating institutes. The quantification methods used by the participating

institutes included external calibration, standard addition and isotope

dilution mass spectrometry (IDMS).

Valid participants’ results from APMP.QM-S10 with demonstrated

metrological traceability were used to calculate the SCRVs. The SCRVs for

zinc and manganese were derived from the median of 10 valid participants’

results and the SCRVs for calcium and magnesium were derived from the

median of 8 valid participants’ results.

The standard uncertainties of SCRVs for zinc, manganese, calcium and

magnesium were derived as follow:

𝑢 (SCRV) = 1.25 ×MADe

√n

The expanded uncertainty of the SCRV was estimated as U(SCRV) = 2 x

u(SCRV), where a coverage factor of 2 gives a level of confidence of

approximately 95%. The SCRVs and associated expanded uncertainties

obtained from APMP.QM-S10 were used as the assigned values and

expanded uncertainties in this Final Report on APLAC T107.


(APLAC T107)


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6.2.2. SCRVs and expanded uncertainties of APMP.QM-S10 are summarized as

follows:

Zinc

mg/kg

Manganese

mg/kg

Calcium

mg/kg

Magnesium

mg/kg

SCRV 11 140 3 716 119 500 65 674

Expanded uncertainty 174 19 1 273 449

6.3. Standard deviations for proficiency assessment estimated from the Horwitz

equation are given as follows:


Standard deviation for

proficiency assessment

438

mg/kg

173

mg/kg

3 290

mg/kg

1 979

mg/kg

Relative standard

deviation for


3.9 % 4.6 % 2.8 % 3.0 %

6.4. Overview of participants’ results

6.4.1. Participants’ z-scores for zinc, manganese, calcium and magnesium are

presented graphically in FIGURES I to IV respectively.

6.4.2. The number and percentage of z-scores in the satisfactory range ( z 2.0),

questionable range ( 2.0 < z < 3.0) and unsatisfactory range ( z 3.0) are

summarized as follows:

z-score

Number of Participants (Percentage)


z 2.0 30 (61%) 31 (66%) 20 (43%) 27 (59%)

2.0 < z < 3.0 7 (14%) 7 (15%) 10 (21%) 5 (11%)

z 3.0 12 (24%) 9 (19%) 17 (36%) 14 (30%)

Total: 49 (100%) 47 (100%) 47 (100%) 46 (100%)


(APLAC T107)


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6.4.3. It is possible for the z-scores published in this report to differ slightly from

the z-score that can be calculated using the equation given in Clause 5.1.1.

These differences arise from the necessary rounding of the actual assigned

values and standard deviations for proficiency assessment prior to their

publication in TABLES III and VI.

6.4.4. For reference purposes, participants’ zeta-scores for zinc, manganese,

calcium and magnesium are given in TABLES XI to XIV respectively and

presented graphically in FIGURES IX to XII respectively.

6.4.5. Assigned values, standard deviation for proficiency assessment, robust

average of the participants’ results and robust standard deviation of the

participants’ results are summarized as follows: (for illustration purposes,

values are rounded to four significant figures whenever applicable)

Zinc

mg/kg

Manganese

mg/kg

Calcium

mg/kg

Magnesium

mg/kg

Assigned value based

on SCRV of

APMP.QM-S10

11 140 3 716 119 500 65 670

Standard deviation for


estimated from the

Horwitz equation

438 173 3 290 1 979

Robust average of

participants’ results 10 610 3 571 114 700 64 160

Robust standard

deviation of

participants’ results

996 335 16 760 6 426

Standard uncertainty of

robust average 178 61 3 055 1 184

The robust averages of the participants’ results for zinc, manganese, calcium

and magnesium were calculated in accordance with Algorithm A in ISO

13528:2015 [9.4]. The robust averages of participants’ results for zinc,

manganese, calcium and magnesium were found to be about 95%, 96%,

96% and 98% of the respective assigned values. The robust average of zinc,

manganese, calcium and magnesium were biased slightly lower than the

SCRVs. As observed, the analytical methodologies used by the participants


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of APLAC T107 and the participating institutes of APMP.QM-S10 were

quite similar. For instance, in both studies ICP-MS, ICP-OES/AES and

AAS were the predominant instrumental techniques employed for analysis.

However, NMIs/DIs employed the high precision determination techniques

of isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-

MS) or gravimetric standard addition inductively coupled plasma optical

emission spectrometry (GSA-ICP-OES) so as to achieve smaller

uncertainties of measurement. The observed bias of the robust averages of

participants’ results from the assigned values may be due to other issues like

inappropriate sample preparation/dilution, improper optimization of

analytical instruments for measurement, and use of standard solutions

without proper metrological traceability for calibration. Participants who

got unsatisfactory z-scores should thoroughly investigate their results and

rectify the technical problems identified.

6.4.6. For reference purposes, the kernel density plots derived from the

participants’ results for zinc, manganese, calcium and magnesium are

shown in FIGURES XIII to XVI. The plots are generated by MS Excel Add-

in software which was freely downloaded from Royal Society of Chemistry

[9.6].

The kernel density estimator is a useful method of representing the overall

structure of the participants’ results. The plots for zinc, manganese, calcium

and magnesium suggested that the data were multimodal. The most

prominent modes of zinc, manganese, calcium and magnesium were about

11 000 mg/kg, 3 700 mg/kg, 119 000 mg/kg and 65 500 mg/kg respectively,

which corresponded closely with their assigned values. Some small

dispersive spread modes represent some participants’ results that

significantly differed from the respective assigned values. Those

participants should thoroughly investigate their results and rectify the

technical problems identified.

6.5. Overview of methods of analysis used by participants

6.5.1. The technical information about the methods of analysis for zinc,

manganese, calcium and magnesium used by participants is given in

TABLES VII to X respectively.

6.5.2. Digestion technique: Most of the participants performed the sample

digestion/dissolution by microwave-assisted digestion. Some participants

employed wet digestion or dry ashing for sample digestion. The plots of

participants’ results with respect to the digestion techniques are shown in


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FIGURE XVII to XX. The various digestion techniques used by the

participants are summarized as follows:

Digestion technique Zinc Manganese Calcium Magnesium

Microwave-assisted

digestion 27 26 27 27

Wet digestion 11 11 10 10

Dry ashing 10 9 9 8

Others: block digestion 1 1 1 1

6.5.3. Digestion medium: HNO3 was commonly used by the participants as

digestion media. The various digestion media used by the participants are


Digestion medium Zinc Manganese Calcium Magnesium

HNO3 42 40 41 40

HCl 14 15 14 14

H2SO4 1 1 0 0

H2O2 11 11 11 11

HClO4 1 1 1 1

Aqua regia 3 3 3 3


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6.5.4. Matrix separation: Most of the participants did not carry out matrix

separation. The choice of participants in carrying out matrix separation for

analysis is summarized as follows:

Matrix separation Zinc Manganese Calcium Magnesium

Yes 8 8 8 8

No 40 38 38 37

Information not

provided 1 1 1 1

6.5.5. Quantification: Most of the participants employed external calibration for

quantification. The various quantification methods used by the participants

are summarized as follows:

Quantification Zinc Manganese Calcium Magnesium

External calibration 35 34 34 33

Internal calibration 11 10 11 10

Standard additions 4 4 4 4

Isotope dilution mass

spectrometry 0 0 0 0

6.5.6. Sources of calibration standards: About half of the participants claimed to

use certified reference materials as calibration standards. The source of

calibration standards used by the participants is summarized as follows:

Sources of calibration

standards Zinc Manganese Calcium Magnesium

Certified reference

materials 25 24 22 23

Commercial sources 25 24 23 22


(APLAC T107)


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6.5.7. Use of internal standard(s): Most of the participants did not use internal

standard(s). The plots of participants’ results with respect to the use of

internal standard(s) are shown in FIGURE XXI to XXIV. The number of

participants using internal standard(s) for analysis is summarized as follows:

Use of internal

standard(s) Zinc Manganese Calcium Magnesium

Yes 15 12 13 13

No 34 34 34 33

Information not

provided 0 1 0 0

6.5.8. Analytical instrument(s): Most of the participants used ICP-AES/OES and

Flame AAS for analysis. The plots of participants’ results with respect to

the analytical instruments are shown in FIGURE XXV to XXVIII. The

various analytical instruments used by the participants are summarized as

follows:

Analytical instrument(s) Zinc Manganese Calcium Magnesium

ICP-MS 7 6 3 3

ICP-AES/OES 21 22 24 23

Flame AAS 21 19 20 20

Graphite AAS 0 0 0 0

Others 0 0 0 0


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6.5.9. Correction for recovery: Most of the participants did not carry out correction

for recovery on their submitted results. The plots of participants’ results with

respect to the correction for recovery are shown in FIGURE XXIX to

XXXII. The number of participants performing correction for recovery is


Correction for recovery Zinc Manganese Calcium Magnesium

Yes 7 8 8 7

No 42 39 38 39

Information not

provided 0 0 0 0

6.5.10. Method accreditation: Most of the participants employed accredited

analytical methods for analysis. The plots of participants’ results with

respect to the method accreditation status are shown in FIGURE XXXIII to

XXXVI. The number of participants using accredited/non-accredited

analytical methods and the performance of participants in terms of z-scores

are summarized as follows:

Method accredited Zinc Manganese Calcium Magnesium

Yes 34 29 34 31

No 15 17 13 15

Information not

provided 0 0 0 0


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Use of accredited

analytical method(s) Zinc Manganese Calcium Magnesium

z 2.0

(Satisfactory) 24 (71%) 19 (66%) 15 (44%) 20 (65%)

2.0 < z < 3.0

(Questionable) 4 (12%) 5 (17%) 8(24%) 3 (10%)

z 3.0

(Unsatisfactory) 6 (18%) 5 (32%) 11 (32%) 8 (26%)

Total: 34 (100%) 29 (100%) 34 (100%) 31 (100%)

Use of non-accredited

analytical method(s) Zinc Manganese Calcium Magnesium

z 2.0

(Satisfactory) 6 (40%) 11 (65%) 5 (38%) 7 (47%)

2.0 < z < 3.0

(Questionable) 3 (20%) 2 (12%) 2 (15%) 2 (13%)

z 3.0

(Unsatisfactory) 6 (40%) 4 (24%) 6 (46%) 6 (40%)

Total: 15 (100%) 17 (100%) 13 (100%) 15 (100%)

The number of participating laboratories using accredited analytical

methods was higher than those employing non-accredited methods for

analysis. The accredited laboratories demonstrated better performance than

the non-accredited counterparts in the determination of zinc, manganese,

calcium and magnesium in terms of a satisfactory rating (z 2.0). This

illustrates the usefulness of accreditation for such common testing

parameters.

Nevertheless, participants who got unsatisfactory z-scores irrespective of

the method accreditation status should thoroughly investigate their results

and rectify the technical problems identified.


(APLAC T107)


Page 19 of 108

6.6. Measurement uncertainty

6.6.1. Although the measurement uncertainties reported by participants were not

used in assessing the performance of participants, estimation of

measurement uncertainty is one of the important technical requirements of

ISO/IEC 17025:2017 [9.7].

6.6.2. The number of participants reporting measurement uncertainty is given as

follows:

Measurement

uncertainty Zinc Manganese Calcium Magnesium

Reported 42 40 40 39

Not reported 7 7 7 7

7. Recommendations

7.1. Further laboratory capacity building efforts in respect of the estimation of

measurement uncertainty are recommended for the participants who showed some

difficulties in reporting measurement uncertainty. It was noted that either the

measurement uncertainty was not reported or the reported measurement uncertainty

was underestimated or overestimated (e.g. reporting a relative expanded uncertainty

of < 1% or a relative expanded uncertainty of > 100% for the concerned

measurements). Those participants should follow published guidelines in

quantifying measurement uncertainty in analytical measurements (e.g. Eurachem

Guide) [9.8].

7.2. It was stipulated in the Result Proforma (APPENDIX V) that analytical results

should be reported to three significant figures. Measurement uncertainty should

also tally with the reported results. Participants who reported analytical

results/measurement uncertainties with excessive significant figures should

carefully review their methods of reporting results.

8. Acknowledgements and remarks

8.1. Participants are requested to check the correctness of their results given in TABLES

III to VI and the technical information in TABLES VII to X. Participants should

inform the organizer via email [email protected] if there are

discrepancies or comments.



(APLAC T107)


Page 20 of 108

8.2. Contributions from all accreditation bodies and participants to this programme are

gratefully noted. Special thanks are extended to APLAC PT Committee, APMP

TCQM, APMP DEC for their support to the programme.

8.3. If the participants have any queries about this report, please contact the coordinator

of this proficiency testing programme as follows:

Government Laboratory

7/F., Homantin Government Offices, 88 Chung Hau Street, Kowloon, Hong Kong

Contact person: Dr. Yuk-tai TSOI

E-mail: [email protected]

8.4. Use of this report by participants shall only be allowed with the written permission

of the coordinator of this proficiency testing programme.

9. References

9.1. W. Horwitz, Anal. Chem. 1982, 54, 67A-76A “Evaluation of analytical methods

used for regulations of food and drugs”.

9.2. CCQM Inorganic Analysis Working Group – Minutes of the Meeting held on 26 –

28 September 2017, Turin, Italy; 16 – 18 April 2018, Sèvres, France

9.3. CAC/GL 55-2005 “Guidelines for vitamin and mineral food supplements”, 2005,

CODEX Alimentarius Commission.

9.4. ISO 13528:2015 “Statistical methods for use in proficiency testing by

interlaboratory comparison”, 2015, Geneva, Switzerland.

9.5. ISO/IEC 17043:2010 “Conformity assessment – General requirements for

proficiency testing”, 2010, Geneva, Switzerland.

9.6. Royal Society of Chemistry Downloaded from:

http://www.rsc.org/Membership/Networking/InterestGroups/Analytical/AMC/Sof

tware/kerneldensities.asp

9.7. ISO 17025:2017 “General requirements for the competence of testing and

calibration laboratories”, 2017, Geneva, Switzerland.

9.8. Eurachem Guide: Quantifying Uncertainty in Analytical Measurement, 3rd Edition,

2012.

9.9. ISO Guide 35:2006 “Reference materials – General and statistical principles for

certification”, 2006, Geneva, Switzerland.


(APLAC T107)


Page 21 of 108

9.10. TABLE I: Programme schedule

Time schedule Phase

24 November 2016 Call for participation

9 December 2016 Deadline for registration

December 2016 Distribution of samples

31 March 2017 Deadline for submission of results

30 June 2017 Interim Report for checking

June 2018 Draft Final Report for Joint APMP-APLAC PT Working

Groups comments

September 2018 Issue of Final Report


(APLAC T107)


Page 22 of 108

TABLE II: Geographical distribution of participants

No. Economies Participants

Enrolled

Returned

Results

Returned

Results

(Zinc)

Returned

Results

(Manganese)

Returned

Results

(Calcium)

Returned

Results

(Magnesium)

1 Australia 4 4 4 4 4 4

2 Canada 2 2 2 2 2 2

3 China 4 4 4 4 4 4

4 Hong Kong,

China 2 2 2 2 2 2

5 India 5 5 5 5 5 5

6 Indonesia 1 1 1 1 1 1

7 Japan 2 2 2 2 2 2

8 Kingdom of

Saudi Arabia 1 1 1 1 1 1

9 Malaysia 2 2 2 2 2 2

10 Mexico 3 3 3 2 1 1

11 Myanmar 2 2 2 2 2 2

12 Pakistan 3 3 3 3 3 3

13 Philippines 3 3 3 2 3 2

14 Republic of

Korea 4 4 3 3 3 2

15 Sri Lanka 3 2 2 2 2 2

16 Taiwan 4 4 3 3 3 4

17 Thailand 1 1 1 1 1 1

18 United States of

America 4 4 4 4 4 4

19 Việt Nam 3 3 2 2 2 2

Total: 53 52 49 47 47 46


(APLAC T107)


Page 23 of 108

TABLE III: Participants’ results and the z-scores for zinc

Assigned

Lab No.

Mass Fraction of

Zinc (mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

z-score Method

Accreditation

1 9030 550 2 1100 -4.81 Yes

2 9.49x10^3 2.49x10^2 2 4.98x10^2 -3.76 Yes

3 1574 0.016 2 0.032 -21.82 Yes

4 1.02x104 3.88x102 2 7.76x102 -2.14 No

5 9621.868 NA NA NA -3.46 Yes

6 10178.301 0.01 2 0.02 -2.19 No

7 9685.804 178.223 2.0 356.446 -3.32 No

8 11266 45.65±0.33 2 45.65±0.77 0.29 Yes

9 1.02x104 --- --- --- -2.14 No

10 *** *** *** *** *** ***

11 1.13x104 86.8 2 174 0.36 No

12 1.13x104 2.69x102 2 5.39x102 0.36 Yes

13 1.05x104 125 2 250 -1.46 Yes

14 7.54x104 3.50x103 2 7.00x103 146.58 Yes

15 1.10x104 0.05x104 2 0.10x104 -0.32 Yes

16 10500 0.022 --- --- -1.46 Yes

17 11500 395 2 790.512 0.82 Yes

18 11100 14.5 2.92 42.3 -0.09 Yes

19 5110 277 2 554 -13.75 No

20 10700 --- --- --- -1.00 No

21 9700 --- --- --- -3.28 Yes

22 11900 237 2 474 1.73 Yes

23 10100 --- --- --- -2.37 Yes

24 11500 865 1.96 1730 0.82 Yes

25 10200 47.6 2 95 -2.14 Yes


(APLAC T107)


Page 24 of 108

Assigned

Lab No.

Mass Fraction of

Zinc (mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

z-score Method

Accreditation

26 11600 766 2 1540 1.05 Yes

27 10508 154 2 308 -1.44 Yes

28 11500 492 2 984 0.82 Yes

29 7278.700 3118.063 3.18 9915.439 -8.81 No

30 10900 --- --- --- -0.55 Yes

31 10847.157 612.864 2 1225.729 -0.67 Yes

32 11271.683 119.132 1.96 233.498 0.30 No

33 xxx xxx xxx xxx xxx xxx

34 11300 1980 2 3960 0.36 No

35 10900 1900 2 3800 -0.55 Yes

36 10300 214 4.303 919 -1.92 Yes

37 1.22x104 98.5 1.96 193 2.42 Yes

38 10792 --- --- 1619 -0.79 No

39 10522.273 113.780 2 227.560 -1.41 Yes

40 *** *** *** *** *** ***

41 11200 7.03 2 14.06 0.14 Yes

42 10900 0.026 2 565 -0.55 Yes

43 11420 550 2 1100 0.64 Yes

44 *** *** *** *** *** ***

45 *** *** *** *** *** ***

46 10400 200 2 400 -1.69 No

47 10700 111 2 223 -1.00 Yes

48 11772 194 2 388 1.44 Yes

49 9309.939 85.185 2 170.372 -4.17 No

50 10088 505 2 1010 -2.40 Yes

51 8776.858 14.451 2 28.901 -5.39 No

52 10915 1.437 2 2.875 -0.51 Yes


(APLAC T107)


Page 25 of 108

Assigned

Lab No.

Mass Fraction of

Zinc (mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

z-score Method

Accreditation

53 8356.287 2.487 2 4.974 -6.35 No

54 11900 1380 2 2760 1.73 Yes

“---” Data or information was not provided.

“xxx” The participant nomination was cancelled by the Accreditation Body.

“***” The registered participant did not submit the results before the deadline.


(APLAC T107)


Page 26 of 108

TABLE IV: Participants’ results and the z-scores for manganese

Assigned

Lab No.

Mass Fraction of

Manganese

(mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

z-score Method

Accreditation

1 3750 221 2 442 0.20 ---

2 *** *** *** *** *** ***

3 2466 0.022 2 0.044 -7.25 Yes

4 3.30x103 1.37x102 2 2.75x102 -2.41 No

5 4326.990 NA NA NA 3.54 Yes

6 1357.629 0.014 2 0.027 -13.67 No

7 3292.651 53.160 2.0 106.320 -2.45 No

8 3902 49.53±0.30 2 49.53±0.68 1.08 Yes

9 3.31x103 --- --- --- -2.35 No

10 *** *** *** *** *** ***

11 3.46x103 26.4 2 52.9 -1.48 No

12 3.26x103 7.95x101 2 1.59x102 -2.64 Yes

13 3.85x103 43.3 2 86.6 0.78 Yes

14 4.57x103 1.89x102 2 3.78x102 4.95 Yes

15 3.88x103 0.17x103 2 0.34x103 0.95 Yes

16 3350 0.053 --- --- -2.12 Yes

17 3960 145 2 290.1214 1.41 Yes

18 3780 20.4 2.92 60.0 0.37 Yes

19 1500 27.3 2 54.6 -12.85 No

20 3660 --- --- --- -0.32 No

21 2520 --- --- --- -6.93 Yes

22 3730 28.7 2 57.4 0.08 Yes

23 3660 --- --- --- -0.32 Yes

24 3880 290 1.96 582 0.95 Yes

25 3530 26.7 2 53 -1.08 Yes


(APLAC T107)


Page 27 of 108

Assigned

Lab No.

Mass Fraction of

Manganese

(mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

z-score Method

Accreditation

26 3610 238 2 476 -0.61 Yes

27 3350 53.4 2 107.0 -2.12 Yes

28 3700 159 2 318 -0.09 Yes

29 3429.732 80.661 3.18 256.503 -1.66 No

30 3560 --- --- --- -0.90 Yes

31 3618.198 177.292 2 354.583 -0.57 Yes

32 3510.165 9.960 1.96 19.521 -1.19 No


34 3790 341 2 682 0.43 No

35 3640 455 2 910 -0.44 No

36 3650 73.7 4.303 317 -0.38 Yes

37 4.17x103 79.9 1.96 157 2.63 Yes

38 3771 NA NA 566 0.32 No

39 3461.808 40.042 2 80.084 -1.47 Yes

40 *** *** *** *** *** ***

41 4020 6.34 2 12.68 1.76 Yes

42 3660 0.024 2 176 -0.32 No

43 3656 150 2 300 -0.35 Yes

44 *** *** *** *** *** ***

45 *** *** *** *** *** ***

46 3620 100 2 200 -0.56 No

47 3720 72.6 2 145 0.02 Yes

48 3674 67 2 134 -0.24 Yes

49 2997.198 27.394 2 54.759 -4.17 No

50 3636 182 2 364 -0.46 No

51 2746.297 10.161 2 20.322 -5.62 No

52 3494 0.429 2 0.859 -1.29 Yes


(APLAC T107)


Page 28 of 108

Assigned

Lab No.

Mass Fraction of

Manganese

(mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

z-score Method

Accreditation

53 2976.178 0.988 2 1.976 -4.29 Yes

54 *** *** *** *** *** ***





(APLAC T107)


Page 29 of 108

TABLE V: Participants’ results and the z-scores for calcium

Assigned

Lab No.

Mass Fraction of

Calcium (mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

z-score Method

Accreditation

1 91600 11400 2 22800 -8.48 Yes

2 1.12x10^5 2.12x10^3 2 4.23x10^3 -2.28 Yes

3 5281 mg/100g 0.027 2 0.054 -20.27 Yes

4 1.14x105 3.50x103 2 7.01x103 -1.67 No

5 77414.632 NA NA NA -12.79 Yes

6 19298.939 0.012 2 0.024 -30.45 No

7 111236.902 1436.863 2.0 2873.726 -2.51 Yes

8 121421 318.71±1.51 2 318.71±3.88 0.58 Yes

9 9.02x104 --- --- --- -8.90 No

10 *** *** *** *** *** ***

11 9.72x104 1.30x103 2 2.59x103 -6.78 No

12 1.11x105 2.25x103 2 4.50x103 -2.58 Yes

13 1.22x105 1.66x103 2 3.32x103 0.76 Yes

14 1.23x105 5.43x103 2 1.09x104 1.06 Yes

15 1.19x105 0.07x105 2 0.14x105 -0.15 Yes

16 108000 0.037 --- --- -3.49 Yes

17 127000 5013 2 10025.1 2.28 Yes

18 121000 217 2.92 634 0.46 Yes

19 54300 3770 2 7540 -19.81 No

20 124000 --- --- --- 1.37 No

21 11600 --- --- --- -32.79 Yes

22 161000 2800 2 5600 12.61 Yes

23 114000 --- --- --- -1.67 Yes

24 127000 9550 1.96 19100 2.28 Yes

25 127000 678 2 1360 2.28 Yes


(APLAC T107)


Page 30 of 108

Assigned

Lab No.

Mass Fraction of

Calcium (mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

z-score Method

Accreditation

26 113000 3503 2 7006 -1.98 Yes

27 113625 3038 2 6077 -1.79 Yes

28 114000 5040 2 10100 -1.67 Yes

29 107958.448 1763.347 3.18 5607.442 -3.51 No

30 111000 --- --- --- -2.58 Yes

31 115197.503 6854.251 2 13708.503 -1.31 Yes

32 *** *** *** *** *** ***


34 127000 14000 2 27900 2.28 No

35 120000 15000 2 30000 0.15 No

36 119000 4790 4.303 20600 -0.15 Yes

37 1.27x105 714 1.96 1.40x103 2.28 Yes

38 114200 --- --- 17130 -1.61 Yes

39 121443.877 1486.279 2 2972.559 0.59 Yes

40 *** *** *** *** *** ***

41 142000 6.44 2 12.88 6.84 Yes

42 136000 0.034 2 9239 5.01 Yes

43 125401 6000 2 12000 1.79 Yes

44 *** *** *** *** *** ***

45 132840.90 4772.20 2 9544.41 4.05 Yes

46 124000 1000 2 2000 1.37 No

47 *** *** *** *** *** ***

48 117536 1784 2 3567 -0.60 Yes

49 120198.989 1123.861 2 2248.923 0.21 No

50 135786 6800 2 13600 4.95 No

51 127033.500 80.499 2 160.990 2.29 No

52 40268 5.333 2 10.666 -24.08 Yes


(APLAC T107)


Page 31 of 108

Assigned

Lab No.

Mass Fraction of

Calcium (mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

z-score Method

Accreditation

53 65936.745 36.841 2 73.682 -16.28 Yes

54 *** *** *** *** *** ***





(APLAC T107)


Page 32 of 108

TABLE VI: Participants’ results and the z-scores for magnesium

Assigned

Lab No.

Mass Fraction of

Magnesium (mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

z-score Method

Accreditation

1 65700 6150 2 12300 0.01 Yes

2 *** *** *** *** *** ***

3 1285 mg/100g 0.003 2 0.006 -26.69 Yes

4 6.26x104 1.92x103 2 3.84x103 -1.55 No

5 68854.378 NA NA NA 1.61 Yes

6 55721.968 0.032 2 0.063 -5.03 No

7 62237.597 922.111 2.0 1844.222 -1.74 No

8 68197 25.61±0.20 2 25.61±0.43 1.28 Yes

9 6.26x104 --- --- --- -1.55 No

10 *** *** *** *** *** ***

11 5.31x104 1.65x103 2 3.29x103 -6.35 No

12 6.04x104 2.68x103 2 5.36x103 -2.67 Yes

13 6.55x104 819 2 1.64x103 -0.09 Yes

14 1.27x104 8.77x102 2 1.75x103 -26.77 Yes

15 6.96x104 0.30x104 2 0.60x104 1.98 Yes

16 57200 0.064 --- --- -4.28 Yes

17 68400 2227 2 4454.142 1.38 Yes

18 66000 315 2.92 920 0.16 Yes

19 30500 2060 2 4120 -17.78 No

20 64900 --- --- --- -0.39 No

21 46400 --- --- --- -9.74 Yes

22 66800 1800 2 3590 0.57 Yes

23 67700 --- --- --- 1.02 Yes

24 71000 5350 1.96 10700 2.69 Yes

25 61800 451 2 903 -1.96 Yes


(APLAC T107)


Page 33 of 108

Assigned

Lab No.

Mass Fraction of

Magnesium (mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

z-score Method

Accreditation

26 64400 3220 2 6440 -0.64 Yes

27 65368 2598 2 5196 -0.15 Yes

28 65800 2830 2 5660 0.06 Yes

29 62052.600 3819.234 3.18 12145.165 -1.83 No

30 65200 --- --- --- -0.24 Yes

31 56353.985 2817.699 2 5635.399 -4.71 Yes

32 *** *** *** *** *** ***


34 72900 8400 2 16800 3.65 No

35 66600 8320 2 16600 0.47 No

36 63400 1520 4.303 6530 -1.15 Yes

37 7.13x104 558 1.96 1.09x103 2.84 Yes

38 63515 --- --- 9527 -1.09 Yes

39 65643.369 608.977 2 1217.954 -0.02 Yes

40 *** *** *** *** *** ***

41 75000 9.25 2 18.50 4.71 Yes

42 72200 0.037 2 5342 3.30 Yes

43 69212 3000 2 6000 1.79 Yes

44 80000 0.0053 2 0.0106 7.24 No

45 *** *** *** *** *** ***

46 60300 2200 2 4400 -2.72 No

47 *** *** *** *** *** ***

48 63682 699 2 1398 -1.01 Yes

49 67147 635.889 2 1271.106 0.74 No

50 70862 3550 2 7100 2.62 No

51 59341.55 37.799 2 75.598 -3.20 No

52 66252 8.704 2 17.408 0.29 Yes


(APLAC T107)


Page 34 of 108

Assigned

Lab No.

Mass Fraction of

Magnesium (mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

z-score Method

Accreditation

53 47373.763 10.518 2 21.036 -9.25 Yes

54 *** *** *** *** *** ***





(APLAC T107)


Page 35 of 108

TABLE VII: Technical information – methods of analysis of zinc

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix

Separation Quantification

Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery

Additional Information

1 Dry ashing HNO3 No External

calibration

Commercial:

Merck, No. Cat:

1.19806

No Flame AAS No ---


calibration

Commercial:

Ajax Finechem No Flame AAS No

AOAC 985.35

(Modified)

3

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: NIST

Std. Yes Flame AAS No ---

4 Wet

digestion

HNO3,

HCl, H2O2 No

External

calibration

CRM: CRMs

MIX

Commercial:

accustandard

No ICP-AES No ---

5

Microwave-

assisted

digestion

HNO3 No Internal

calibration

CRM: NIST

traceable

standards

No ICP-OES No ---

6

Microwave-

assisted

digestion

HNO3,

HClO4 No

External

calibration

CRM: Loba

chemie

LM07091610

No Flame AAS No

Used Flame AAS

instead of ICP-MS to

accreditation method

AOAC 984.27

7

Microwave-

assisted

digestion

HNO3 No External

calibration

Commercial:

Sigma Aldrich

Lot: BCBR

0978V Valid up

to Jan 20

No ICP-AES No ---

8

Microwave-

assisted

digestion

HNO3 No Internal

calibration

CRM: High

Purity Standard

Yes;

Germanium ICP-MS No ---

9

Microwave-

assisted

digestion

HNO3 No External

calibration

Commercial:

Sigma Aldrich No Flame AAS No ---

10 *** *** *** *** *** *** *** *** ***

11

Microwave-

assisted

digestion

HNO3,

H2O2 No

External

calibration

Commercial: Zn

AAS standard

solution Reage

con

No Flame AAS No None

12

Microwave-

assisted

digestion

HNO3,

H2O2 No

External

calibration

CRM:

GBW08620

National

Institute of

Metrology,

China

No Flame AAS No ---

13

Microwave-

assisted

digestion

HNO3,

HCl No

External

calibration --- No ICP-AES No ---

14

Microwave-

assisted

digestion

HNO3 Yes External

calibration --- No ICP-MS No ---

15

Microwave-

assisted

digestion

HNO3 Yes External

calibration --- No Flame AAS No ---


(APLAC T107)


Page 36 of 108

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix


Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery


16 Wet

digestion

HNO3,

HCl No

External

calibration

Commercial:

Ultra Scientific No ICP-AES No ---

17

Microwave-

assisted

digestion

HNO3 No

External

calibration

and Standard

additions

CRM: SRM

1849a

Commercial:

High Purity

No ICP-AES Yes; 85% ---

18

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: FDA RM

"Cocoa Powder"

Commercial:

Inorganic

Ventures

Yes;

Yttrium ICP-AES No

Method used: FDA

Elemental Analysis

Manual (EAM)

4.4/KAN-LAB-

MET.092

19 Dry ashing HCl No Internal

calibration

Commercial:

KANTO

CHEMICAL

CO., INC.

Yes;

Yttrium ICP-AES No ---

20 Wet

digestion HNO3 No

Internal

calibration --- Yes; 72Ge ICP-MS

Yes;

104% ---

21 Dry ashing Aqua

regia No

External

calibration

Commercial:

Merck/Sigma No Flame AAS No ---


calibration

Commercial:

Merck No Flame AAS No ---

23

Others:

Block

Digestion

HNO3 Yes Internal

calibration --- Yes ICP-AES No ---

24 Wet

digestion

Aqua

regia No

Internal

calibration

CRM: High

purity Standards

P/N 10M68-1

Yes;

Tellurium ICP-AES No ---

25 Wet

digestion HNO3 No

External

calibration

CRM: Sigma

TraceCert std No Flame AAS No ---

26

Microwave-

assisted

digestion

HNO3,

HCl,

H2O2,

Aqua

regia

No External

calibration

Commercial:

CPA Chem

Yes;

Lutetium ICP-AES No ---

27 Wet

digestion HCl No

Internal

calibration CRM: Merck No ICP-AES No ---

28 Dry ashing HNO3 Yes Internal

calibration

CRM:

PlasmaCAL

10030

±30µg/mL Zn

Commercial:

NA

Yes;

PROMIL

Lot No:

608373517

K

Flame AAS Yes;

93.6% None

29

Microwave-

assisted

digestion

HNO3,

HCl No

External

calibration

CRM: None

Commercial:

Inorganic

Ventures: ISO-

CAL-12, Lot:

K2-

mMEB620107

Yes ICP-MS No

In house method PE-

2118, the method is

accredited but not for

this measurand.

30 Wet

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Agilent 5183-

4688

Yes ICP-AES No ---


(APLAC T107)


Page 37 of 108

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix


Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery


31

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: VHG

LABS No ICP-AES No EPA 6010 D 2014

32 Wet

digestion

Others:

8ml HNO3

+ 2ml

H2SO4

No External

calibration

CRM: zinc

standard for

AAS, Lote

BCBR0978V

Commercial:

Sigma-Aldrich

Tracecert

No Flame AAS No Accreditation on NMX-

AA-051-SCFI-2001

33 xxx xxx xxx xxx xxx xxx xxx xxx xxx

34

Microwave-

assisted

digestion

HNO3,

H2O2 NA

Internal

calibration

CRM: High

purity - Zn

1000ppm

Yes; Li, Sc,

Ge, Rh, Lu ICP-MS No

Our accredited method

is reported on received

basis and not on a dry

mass basis (no moisture

correction) and our

accredited method for

moisture determination

is different from the

instruction and

therefore we count our

reported result is

analysed by an non-

accredited method

35

Microwave-

assisted

digestion

HNO3,

HCl No

External

calibration

Commercial:

High purity

standard

Yes; Sc ICP-MS No ---

36

Microwave-

assisted

digestion

HNO3,

HCl No

External

calibration

Commercial:

Inorganic

Ventures

Yes;

Indium,

Yttrium

ICP-AES No ---

37 Wet

digestion HNO3 No

External

calibration CRM: NIST

Yes;

Yttrium ICP-MS No ---

38

Microwave-

assisted

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Use reference

material

No ICP-AES No ---

39

Microwave-

assisted

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Scharlau

Product:

CI0126, Batch

16405301

No Flame AAS Yes;

97.7% ---

40 *** *** *** *** *** *** *** *** ***

41

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: ICUS-

613 Unichrom No ICP-AES No ---

42

Microwave-

assisted

digestion

HNO3 Yes External

calibration

Commercial:

Ultra Scientific No Flame AAS No ---

43

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: NIST

SRM 1548a

Commercial:

Merck & High-

Purity

No ICP-AES No ---


(APLAC T107)


Page 38 of 108

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix


Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery


44 *** *** *** *** *** *** *** *** ***

45 *** *** *** *** *** *** *** *** ***

46

Microwave-

assisted

digestion

HNO3 No Standard

additions

CRM:

AccuStandard

(USA)

No ICP-AES Yes;

110% ---

47 Dry ashing HCl No External

calibration

CRM: NIST

3168a No ICP-AES No ---


calibration

CRM:

AccuStandard,

Inc.

No Flame AAS No ---

49 Dry ashing HNO3,

HCl No

Internal


50 Wet

digestion

HNO3,

HCl Yes

Standard

additions CRM: Scharlau No Flame AAS Yes; 98% ---

51 Dry ashing HCl Yes External

calibration

CRM: Certipur

SRM from

NIST

No Flame AAS No NA

52

Microwave-

assisted

digestion

HNO3,

H2O2 Yes

Standard

additions

Commercial:

Perkin Elmer No Flame AAS No ---

53 Wet

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Merck,

Germany

No Flame AAS Yes;

100% ---

54

Microwave-

assisted

digestion

HNO3,

H2O2 No

External

calibration

CRM:

ULTRASCIEN

TIFIC LOTE

CP-0155 CAD

02-28-2023

10000 mg/L

No Flame AAS No ---





(APLAC T107)


Page 39 of 108

TABLE VIII: Technical information – methods of analysis of manganese

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix


Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery



calibration

Commercial:

Merck, No. Cat:

1.19789

No Flame AAS Yes ---

2 *** *** *** *** *** *** *** *** ***

3

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: NIST


4 Wet

digestion

HNO3,

HCl, H2O2 No

External

calibration

CRM: CRMs

MIX

Commercial:

Accustandard

No ICP-AES No ---

5

Microwave-

assisted

digestion

HNO3 No Internal

calibration

CRM: NIST

traceable

standards

No ICP-OES No Nil

6

Microwave-

assisted

digestion

HNO3,

HClO4 No

External

calibration

CRM: Loba

chemie Lot No

LM10031512

No Flame AAS No

Used Flame AAS



AOAC 984.27

7

Microwave-

assisted

digestion

HNO3 No External

calibration

Commercial:

Sigma Aldrich

Lot:

BCB80416V

Expiry Date

May 20

No ICP-AES No ---

8

Microwave-

assisted

digestion

HNO3 No Internal

calibration

CRM: High

Purity Standard

Yes;


9

Microwave-

assisted

digestion

HNO3 No External

calibration

Commercial:


10 *** *** *** *** *** *** *** *** ***

11

Microwave-

assisted

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Mn AAS

standard

solution Fluka,

Sigma Aldrich


12

Microwave-

assisted

digestion

HNO3,

H2O2 No

External

calibration

CRM:

GBW(E)080157

National

Institute of

Metrology,

China

No Flame AAS No ---

13

Microwave-

assisted

digestion

HNO3,

HCl No

External


14

Microwave-

assisted

digestion

HNO3 Yes External



(APLAC T107)


Page 40 of 108

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix


Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery


15

Microwave-

assisted

digestion

HNO3 Yes External


16 Wet

digestion

HNO3,

HCl No

External

calibration

Commercial:


17

Microwave-

assisted

digestion

HNO3 No

External

calibration

and Standard

additions

CRM: SRM

1849a

Commercial:

High Purity

No ICP-AES Yes;

88.9% ---

18

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: NIST

1566b and FDA

RM "Cocoa

Powder"

Commercial:

Inorganic

Ventures

Yes;

Yttrium ICP-AES No

Method used: FDA

Elemental Analysis

Manual (EAM)

4.4/KAN-LAB-

MET.092


calibration

Commercial:

KANTO

CHEMICAL

CO., INC.

Yes;


20 Wet

digestion HNO3 No

External

calibration --- --- ICP-MS

Yes;

100% ---

21 Dry ashing Aqua

regia No

External

calibration

Commercial:



calibration

Commercial:


23

Others:

Block

Digestion

HNO3 Yes Internal


24 Wet

digestion

Aqua

regia No

Internal

calibration

CRM: High

purity Standards

P/N 100032-1

Yes;

Tellurium ICP-AES No ---

25 Wet

digestion HNO3 No

External

calibration

CRM: Sigma


26

Microwave-

assisted

digestion

HNO3,

HCl,

H2O2,

Aqua

regia

No External

calibration

Commercial:

CPA Chem

Yes;


27 Wet

digestion HCl No

Internal



calibration

CRM:

PlasmaCAL

10000

±60µg/mL Mn

Commercial:

NA

Yes;

PROMIL

Lot No:

608373517

K

Flame AAS Yes;

101.4% None

29

Microwave-

assisted

digestion

HNO3,

HCl No

External

calibration

CRM: None

Commercial:

Inorganic

Ventrues: ISO-

CAL-12, Lot:

K2-

MEB620107

No ICP-MS No

In house method PE-

2118, the method is


this measurand.


(APLAC T107)


Page 41 of 108

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix


Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery


30 Wet

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Agilent 5183-

4688

Yes ICP-AES No ---

31

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: VHG


32 Wet

digestion

Others:

8ml HNO3

+ 2ml

H2SO4

No External

calibration

CRM:

manganese

standard for

AAS, Lote

BCBP5341V

Commercial:

Sigma-Aldrich

Tracecert

No Flame AAS No Accreditation on NMX-

AA-051-SCFI-2001


34

Microwave-

assisted

digestion

HNO3,

H2O2 NA

Internal

calibration

CRM: High

purity - Mn

1000ppm

Yes; Li, Sc,

Ge, Rh, Lu ICP-MS No





correction) and our




instruction and


reported result is

analysed by an non-

accredited method

35

Microwave-

assisted

digestion

HNO3,

HCl No

External

calibration

Commercial:

High purity

standard

No ICP-AES No ---

36

Microwave-

assisted

digestion

HNO3,

HCl No

External

calibration

Commercial:

Inorganic

Ventures

Yes;

Indium,

Yttrium

ICP-AES No ---

37 Wet

digestion

HNO3,

HCl, H2O2 No

External


Yes;


38

Microwave-

assisted

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Use reference

material

No ICP-AES No ---

39

Microwave-

assisted

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Scharlau

Product:

MA0111, Batch

16698601

No Flame AAS Yes;

98.4% ---

40 *** *** *** *** *** *** *** *** ***

41

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: ICUS-


42

Microwave-

assisted

digestion

HNO3 Yes External

calibration

Commercial:

J.T. Baker No Flame AAS No ---


(APLAC T107)


Page 42 of 108

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix


Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery


43

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: NIST

SRM 1548a

Commercial:

Merck & High-

Purity

No ICP-AES No ---

44 *** *** *** *** *** *** *** *** ***

45 *** *** *** *** *** *** *** *** ***

46

Microwave-

assisted

digestion

HNO3 No Standard

additions

CRM:

AccuStandard

(USA)

No ICP-AES Yes;

110% ---

47 Dry ashing HCl No External

calibration

CRM: NIST

3132 No ICP-AES No ---


calibration

CRM:

AccuStandard,

Inc.

No Flame AAS No ---

49 Dry ashing HNO3,

HCl No

Internal


50 Wet

digestion

HNO3,

HCl Yes

Standard

additions CRM: Merck No Flame AAS Yes; 95% ---


calibration

CRM: Certipur

SRM from

NIST

No Flame AAS No NA

52

Microwave-

assisted

digestion

HNO3,

H2O2 Yes

Standard

additions

Commercial:


53 Wet

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Merck,

Germany

No Flame AAS Yes;

102% ---

54 *** *** *** *** *** *** *** *** ***





(APLAC T107)


Page 43 of 108

TABLE IX: Technical information – methods of analysis of calcium

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix


Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery



calibration

Commercial:

Merck, No. Cat:

1.19778

No Flame AAS No ---


calibration

Commercial:

Ajax Finechem No Flame AAS No

AOAC 985.35

(Modified)

3

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: NIST


4 Wet

digestion

HNO3,

HCl, H2O2 No

External

calibration

CRM: CRMs

MIX

Commercial:

Accustandard

No ICP-AES --- ---

5

Microwave-

assisted

digestion

HNO3 No Internal

calibration

CRM: NIST

traceable

standards

No ICP-OES No Nil

6

Microwave-

assisted

digestion

HNO3,

HClO4 No

External

calibration

CRM: Loba

chemie

LM05591311

No Flame AAS No

Used Flame AAS



AOAC 984.27

7

Microwave-

assisted

digestion

HNO3 No External

calibration

Commercial:

Sigma Aldrich

Lot: BCBO

6058V Expiry

Date Oct 2018

No ICP-AES No ---

8

Microwave-

assisted

digestion

HNO3 No Internal

calibration

CRM: High

Purity Standard

Yes;


9

Microwave-

assisted

digestion

HNO3 No External

calibration

Commercial:


10 *** *** *** *** *** *** *** *** ***

11

Microwave-

assisted

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Anarar grade

BDH Chemicals

No Flame AAS No ---

12

Microwave-

assisted

digestion

HNO3,

H2O2 No

External

calibration

CRM: GBW

(E)080118

National

Institute of

Metrology,

China

No Flame AAS No ---

13

Microwave-

assisted

digestion

HNO3,

HCl No

External


14

Microwave-

assisted

digestion

HNO3 Yes External


15

Microwave-

assisted

digestion

HNO3 Yes External


16 Wet

digestion

HNO3,

HCl No

External

calibration

Commercial:



(APLAC T107)


Page 44 of 108

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix


Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery


17

Microwave-

assisted

digestion

HNO3 No

External

calibration

and Standard

additions

CRM: SRM

1849a

Commercial:

High Purity

No ICP-AES Yes;

88.6% ---

18

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: FDA RM

"Cocoa Powder"

Commercial:

Inorganic

Ventures

Yes;

Yttrium ICP-AES No

Method used: FDA

Elemental Analysis

Manual (EAM)

4.4/KAN-LAB-

MET.092


calibration

Commercial:

KANTO

CHEMICAL

CO., INC.

Yes;


20 Wet

digestion HNO3 No

External

calibration

and Internal

calibration

--- No Flame AAS Yes;

97.6% ---

21 Dry ashing Aqua

regia No

External

calibration

Commercial:



calibration

Commercial:


23

Others:

Block

Digestion

HNO3 Yes Internal


24 Wet

digestion

Aqua

regia No

Internal

calibration

CRM: High

purity Standards

P/N 10M9-1

Yes;


25 Wet

digestion HNO3 No

External

calibration

CRM: Sigma


26

Microwave-

assisted

digestion

HNO3,

HCl,

H2O2,

Aqua

regia

No External

calibration

Commercial:

High Purity

Standards

Yes;


27 Wet

digestion HCl No

Internal



calibration

CRM:

PlasmaCAL

10000

±30µg/mL Ca

Commercial:

NA

Yes;

PROMIL

Lot No:

608373517

K

Flame AAS Yes;

98.5% None

29

Microwave-

assisted

digestion

HNO3,

HCl No

External

calibration

CRM: None

Commercial:

Inorganic

Ventures: AGQ-

USA-1, Lot K2-

MEB622085

No ICP-AES No

In house method

PEUSA-009, method

and measurand is


this type of matrix.

30 Wet

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Agilent 5183-

4688

Yes ICP-AES No ---

31

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: VHG



(APLAC T107)


Page 45 of 108

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix


Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery


32 *** *** *** *** *** *** *** *** ***


34

Microwave-

assisted

digestion

HNO3,

H2O2 NA

Internal

calibration

CRM: High

purity - Ca

1000ppm

Yes; Eu ICP-AES No





correction) and our




instruction and


reported result is

analysed by an non-

accredited method

35

Microwave-

assisted

digestion

HNO3,

HCl No

External

calibration

Commercial:

High purity

standard

No ICP-AES No ---

36

Microwave-

assisted

digestion

HNO3,

HCl No

External

calibration

Commercial:

Inorganic

Ventures

Yes;

Indium,

Yttrium

ICP-AES No ---

37 Wet

digestion

HNO3,

HCl, H2O2 No

External


Yes;


38

Microwave-

assisted

digestion

HNO3,

H2O2 No

External


39

Microwave-

assisted

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Scharlau

Product:

CA0176, Batch

17503001

No Flame AAS Yes;

97.0% ---

40 *** *** *** *** *** *** *** *** ***

41

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: ICUS-


42

Microwave-

assisted

digestion

HNO3 Yes External

calibration

Commercial:

ACCUStandard No Flame AAS No ---

43

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: NIST

SRM 1548a

Commercial:

Merck & High-

Purity

No ICP-AES Yes ---

44 *** *** *** *** *** *** *** *** ***

45

Microwave-

assisted

digestion

HNO3 No External


46

Microwave-

assisted

digestion

HNO3 No Standard

additions

CRM:

AccuStandard

(USA)

No ICP-AES Yes;

105% ---


(APLAC T107)


Page 46 of 108

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix


Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery


47 *** *** *** *** *** *** *** *** ***


calibration

CRM:

AccuStandard,

Inc.

No Flame AAS No ---

49 Dry ashing HNO3,

HCl No

Internal


50 Wet

digestion

HNO3,

HCl Yes

Standard

additions CRM: Fisher Yes Flame AAS Yes; 96% ---


calibration

CRM: Certipur

SRM from

NIST

No Flame AAS No NA

52

Microwave-

assisted

digestion

HNO3,

H2O2 Yes

Standard

additions

Commercial:


53 Wet

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Merck,

Germany

No Flame AAS Yes;

103% ---

54 *** *** *** *** *** *** *** *** ***





(APLAC T107)


Page 47 of 108

TABLE X: Technical information – methods of analysis of magnesium

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix


Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery



calibration

Commercial:

Merck, No. Cat:

1.19788

No Flame AAS No ---

2 *** *** *** *** *** *** *** *** ***

3

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: NIST


4 Wet

digestion

HNO3,

HCl, H2O2 No

External

calibration

CRM: CRMs

MIX

Commercial:

Accustandard

No ICP-AES No ---

5

Microwave-

assisted

digestion

HNO3 No Internal

calibration

CRM: NIST

traceable

standards

No ICP-OES No Nil

6

Microwave-

assisted

digestion

HNO3,

HClO4 No

External

calibration

CRM: Loba

chemie Lot No

LM04161309

No Flame AAS No

Used Flame AAS



AOAC 984.27

7

Microwave-

assisted

digestion

HNO3 No External

calibration

Commercial:

Sigma Aldrich

Lot:

BCBR3923V

Expiry Date

March 2019

No ICP-AES No ---

8

Microwave-

assisted

digestion

HNO3 No Internal

calibration

CRM: High

Purity Standard

Yes;


9

Microwave-

assisted

digestion

HNO3 No External

calibration

Commercial:


*** *** *** *** *** *** *** *** *** ***

11

Microwave-

assisted

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Analar

Normapur

VWR

Chemicals


12

Microwave-

assisted

digestion

HNO3,

H2O2 No

External

calibration

CRM: GBW

(E)080126

National

Institute of

Metrology,

China

No Flame AAS No ---

13

Microwave-

assisted

digestion

HNO3,

HCl No

External


14

Microwave-

assisted

digestion

HNO3 Yes External



(APLAC T107)


Page 48 of 108

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix


Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery


15

Microwave-

assisted

digestion

HNO3 Yes External


16 Wet

digestion

HNO3,

HCl No

External

calibration

Commercial:


17

Microwave-

assisted

digestion

HNO3 No

External

calibration

and Standard

additions

CRM: SRM

1849a

Commercial:

High Purity

No ICP-AES Yes;

86.1% ---

18

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: FDA RM

"Cocoa Powder"

Commercial:

Inorganic

Ventures

Yes;

Yttrium ICP-AES No

Method used: FDA

Elemental Analysis

Manual (EAM)

4.4/KAN-LAB-

MET.092


calibration

Commercial:

KANTO

CHEMICAL

CO., INC.

Yes;


20 Wet

digestion HNO3 No

External

calibration --- No Flame AAS

Yes;

94.2% ---

21 Dry ashing Aqua

regia No

External

calibration

Commercial:



calibration

Commercial:


23

Others:

Block

Digestion

HNO3 Yes Internal


24 Wet

digestion

Aqua

regia No

Internal

calibration

CRM: High

purity Standards

P/N 10M31-1

Yes;


25 Wet

digestion HNO3 No

External

calibration

CRM: Sigma


26

Microwave-

assisted

digestion

HNO3,

HCl,

H2O2,

Aqua

regia

No External

calibration

Commercial:

High Purity

Standards

Yes;


27 Wet

digestion HCl No

Internal



calibration

CRM:

PlasmaCAL

10000

±30µg/mL Mg

Commercial:

NA

Yes;

PROMIL

Lot No:

608373517

K

Flame AAS Yes;

101.2% None

29

Microwave-

assisted

digestion

HNO3,

HCl No

External

calibration

CRM: None

Commercial:

Inorganic

Ventures, AGQ-

USA-1, Lot:

K2-

MEB622085

No ICP-AES No

In house method

PEUSA-009, method

and measurand is


this type of matrix.


(APLAC T107)


Page 49 of 108

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix


Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery


30 Wet

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Agilent 5183-

4688

Yes ICP-AES No ---

31

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: VHG


32 *** *** *** *** *** *** *** *** ***


34

Microwave-

assisted

digestion

HNO3,

H2O2 NA

Internal

calibration

CRM: High

purity - Mg

1000ppm

Yes; Eu ICP-AES No





correction) and our




instruction and


reported result is

analysed by an non-

accredited method

35

Microwave-

assisted

digestion

HNO3,

HCl No

External

calibration

Commercial:

High purity

standard

No ICP-AES No ---

36

Microwave-

assisted

digestion

HNO3,

HCl No

External

calibration

Commercial:

Inorganic

Ventures

Yes;

Indium,

Yttrium

ICP-AES No ---

37 Wet

digestion

HNO3,

HCl, H2O2 No

External


Yes;


38

Microwave-

assisted

digestion

HNO3,

H2O2 No

External


39

Microwave-

assisted

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Scharlau

Product:

Ma0011, Batch

16688901

No Flame AAS Yes;

98.2% ---

40 *** *** *** *** *** *** *** *** ***

41

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: ICUS-


42

Microwave-

assisted

digestion

HNO3 Yes External

calibration

Commercial:

Ultra Scientific No Flame AAS No ---

43

Microwave-

assisted

digestion

HNO3 No External

calibration

CRM: NIST

SRM 1548a

Commercial:

Merck & High-

Purity

No ICP-AES No ---


(APLAC T107)


Page 50 of 108

Assigned

Lab No.

Digestion

Technique

Digestion

Medium

Matrix


Source(s) of

Calibration

Standard(s)

Use of

Internal

Standard(s)

Analytical

Instrument(s)

Correction

for

Recovery


44

Microwave-

assisted

digestion

HNO3 No External

calibration CRM: NIST Yes, ERA Flame AAS No No

45 *** *** *** *** *** *** *** *** ***

46

Microwave-

assisted

digestion

HNO3 No Standard

additions

CRM:

AccuStandard

(USA)

No ICP-AES Yes;

120% ---

47 *** *** *** *** *** *** *** *** ***


calibration

CRM:

AccuStandard,

Inc.

No Flame AAS No ---

49 Dry ashing HNO3,

HCl No

Internal


50 Wet

digestion

HNO3,

HCl Yes

Standard

additions CRM: ACCU No Flame AAS Yes; 94% ---


calibration

CRM: Certipur

SRM from

NIST

No Flame AAS No NA

52

Microwave-

assisted

digestion

HNO3,

H2O2 Yes

Standard

additions

Commercial:

SCP science No Flame AAS No ---

53 Wet

digestion

HNO3,

H2O2 No

External

calibration

Commercial:

Merck,

Germany

No Flame AAS Yes;

111% ---

54 *** *** *** *** *** *** *** *** ***





(APLAC T107)


Page 51 of 108

TABLE XI: Participants’ results and the zeta-scores for zinc

Assigned

Lab No.

Mass Fraction of

Zinc (mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

zeta-score Method

Accreditation

1 9030 550 2 1100 -3.79 Yes

2 9.49x10^3 2.49x10^2 2 4.98x10^2 -6.26 Yes

3 1574 0.016 2 0.032 -109.95 Yes

4 1.02x104 3.88x102 2 7.76x102 -2.36 No

6 10178.301 0.01 2 0.02 -11.05 No

7 9685.804 178.223 2.0 356.446 -7.33 No

8 11266 45.65±0.33 2 45.65±0.77 1.28 Yes

11 1.13x104 86.8 2 174 1.30 No

12 1.13x104 2.69x102 2 5.39x102 0.57 Yes

13 1.05x104 125 2 250 -4.20 Yes

14 7.54x104 3.50x103 2 7.00x103 18.35 Yes

15 1.10x104 0.05x104 2 0.10x104 -0.28 Yes

16 10500 0.022 --- --- -7.36 Yes

17 11500 395 2 790.512 0.89 Yes

18 11100 14.5 2.92 42.3 -0.45 Yes

19 5110 277 2 554 -20.77 No

22 11900 237 2 474 3.01 Yes

24 11500 865 1.96 1730 0.41 Yes

25 10200 47.6 2 95 -9.48 Yes

26 11600 766 2 1540 0.60 Yes

27 10508 154 2 308 -3.57 Yes

28 11500 492 2 984 0.72 Yes

29 7278.700 3118.063 3.18 9915.439 -1.24 No

31 10847.157 612.864 2 1225.729 -0.47 Yes

32 11271.683 119.132 1.96 233.498 0.89 No


(APLAC T107)


Page 52 of 108

Assigned

Lab No.

Mass Fraction of

Zinc (mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

zeta-score Method

Accreditation

34 11300 1980 2 3960 0.08 No

35 10900 1900 2 3800 -0.13 Yes

36 10300 214 4.303 919 -3.64 Yes

37 1.22x104 98.5 1.96 193 8.07 Yes

39 10522.273 113.780 2 227.560 -4.31 Yes

41 11200 7.03 2 14.06 0.69 Yes

42 10900 0.026 2 565 -2.76 Yes

43 11420 550 2 1100 0.50 Yes

46 10400 200 2 400 -3.39 No

47 10700 111 2 223 -3.12 Yes

48 11772 194 2 388 2.97 Yes

49 9309.939 85.185 2 170.372 -15.03 No

50 10088 505 2 1010 -2.05 Yes

51 8776.858 14.451 2 28.901 -26.80 No

52 10915 1.437 2 2.875 -2.59 Yes

53 8356.287 2.487 2 4.974 -31.98 No

54 11900 1380 2 2760 0.55 Yes



(APLAC T107)


Page 53 of 108

TABLE XII: Participants’ results and the zeta-scores for manganese

Assigned

Lab No.

Mass Fraction of

Manganese

(mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

zeta-score Method

Accreditation

1 3750 221 2 442 0.15 ---

3 2466 0.022 2 0.044 -138.89 Yes

4 3.30x103 1.37x102 2 2.75x102 -3.03 No

6 1357.629 0.014 2 0.027 -262.04 No

7 3292.651 53.160 2.0 106.320 -7.85 No

8 3902 49.53±0.30 2 49.53±0.68 3.69 Yes

11 3.46x103 26.4 2 52.9 -9.18 No

12 3.26x103 7.95x101 2 1.59x102 -5.70 Yes

13 3.85x103 43.3 2 86.6 3.03 Yes

14 4.57x103 1.89x102 2 3.78x102 4.51 Yes

15 3.88x103 0.17x103 2 0.34x103 0.96 Yes

16 3350 0.053 --- --- -40.67 Yes

17 3960 145 2 290.1214 1.68 Yes

18 3780 20.4 2.92 60.0 2.87 Yes

19 1500 27.3 2 54.6 -77.09 No

22 3730 28.7 2 57.4 0.47 Yes

24 3880 290 1.96 582 0.57 Yes

25 3530 26.7 2 53 -6.60 Yes

26 3610 238 2 476 -0.45 Yes

27 3350 53.4 2 107.0 -6.76 Yes

28 3700 159 2 318 -0.10 Yes

29 3429.732 80.661 3.18 256.503 -3.53 No

31 3618.198 177.292 2 354.583 -0.55 Yes

32 3510.165 9.960 1.96 19.521 -15.33 No

34 3790 341 2 682 0.22 No


(APLAC T107)


Page 54 of 108

Assigned

Lab No.

Mass Fraction of

Manganese

(mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

zeta-score Method

Accreditation

35 3640 455 2 910 -0.17 No

36 3650 73.7 4.303 317 -0.89 Yes

37 4.17x103 79.9 1.96 157 5.65 Yes

39 3461.808 40.042 2 80.084 -6.19 Yes

41 4020 6.34 2 12.68 27.61 Yes

42 3660 0.024 2 176 -6.22 No

43 3656 150 2 300 -0.40 Yes

46 3620 100 2 200 -0.96 No

47 3720 72.6 2 145 0.05 Yes

48 3674 67 2 134 -0.62 Yes

49 2997.198 27.394 2 54.759 -24.93 No

50 3636 182 2 364 -0.44 No

51 2746.297 10.161 2 20.322 -71.44 No

52 3494 0.429 2 0.859 -24.64 Yes

53 2976.178 0.988 2 1.976 -81.71 Yes



(APLAC T107)


Page 55 of 108

TABLE XIII: Participants’ results and the zeta-scores for calcium

Assigned

Lab No.

Mass Fraction of

Calcium (mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

zeta-score Method

Accreditation

1 91600 11400 2 22800 -2.44 Yes

2 1.12x10^5 2.12x10^3 2 4.23x10^3 -3.39 Yes

3 5281 mg/100g 0.027 2 0.054 -104.86 Yes

4 1.14x105 3.50x103 2 7.01x103 -1.55 No

6 19298.939 0.012 2 0.024 -157.55 No

7 111236.902 1436.863 2.0 2873.726 -5.26 Yes

8 121421 318.71±1.51 2 318.71±3.88 2.70 Yes

11 9.72x104 1.30x103 2 2.59x103 -15.41 No

12 1.11x105 2.25x103 2 4.50x103 -3.64 Yes

13 1.22x105 1.66x103 2 3.32x103 1.41 Yes

14 1.23x105 5.43x103 2 1.09x104 0.64 Yes

15 1.19x105 0.07x105 2 0.14x105 -0.07 Yes

16 108000 0.037 --- --- -18.08 Yes

17 127000 5013 2 10025.1 1.48 Yes

18 121000 217 2.92 634 2.23 Yes

19 54300 3770 2 7540 -17.05 No

22 161000 2800 2 5600 14.45 Yes

24 127000 9550 1.96 19100 0.78 Yes

25 127000 678 2 1360 8.07 Yes

26 113000 3503 2 7006 -1.83 Yes

27 113625 3038 2 6077 -1.89 Yes

28 114000 5040 2 10100 -1.08 Yes

29 107958.448 1763.347 3.18 5607.442 -6.16 No

31 115197.503 6854.251 2 13708.503 -0.63 Yes

34 127000 14000 2 27900 0.54 No


(APLAC T107)


Page 56 of 108

Assigned

Lab No.

Mass Fraction of

Calcium (mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

zeta-score Method

Accreditation

35 120000 15000 2 30000 0.03 No

36 119000 4790 4.303 20600 -0.10 Yes

37 1.27x105 714 1.96 1.40x103 7.84 Yes

39 121443.877 1486.279 2 2972.559 1.20 Yes

41 142000 6.44 2 12.88 35.38 Yes

42 136000 0.034 2 9239 25.94 Yes

43 125401 6000 2 12000 0.98 Yes

45 132840.90 4772.20 2 9544.41 2.77 Yes

46 124000 1000 2 2000 3.80 No

48 117536 1784 2 3567 -1.04 Yes

49 120198.989 1123.861 2 2248.923 0.54 No

50 135786 6800 2 13600 2.38 No

51 127033.500 80.499 2 160.990 11.75 No

52 40268 5.333 2 10.666 -124.57 Yes

53 65936.745 36.841 2 73.682 -84.08 Yes



(APLAC T107)


Page 57 of 108

TABLE XIV: Participants’ results and the zeta-scores for magnesium

Assigned

Lab No.

Mass Fraction of

Magnesium (mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

zeta-score Method

Accreditation

1 65700 6150 2 12300 0.00 Yes

3 1285 mg/100g 0.003 2 0.006 -235.82 Yes

4 6.26x104 1.92x103 2 3.84x103 -1.59 No

6 55721.968 0.032 2 0.063 -44.43 No

7 62237.597 922.111 2.0 1844.222 -3.62 No

8 68197 25.61±0.20 2 25.61±0.43 11.19 Yes

11 5.31x104 1.65x103 2 3.29x103 -7.55 No

12 6.04x104 2.68x103 2 5.36x103 -1.96 Yes

13 6.55x104 819 2 1.64x103 -0.20 Yes

14 1.27x104 8.77x102 2 1.75x103 -58.52 Yes

15 6.96x104 0.30x104 2 0.60x104 1.31 Yes

16 57200 0.064 --- --- -37.83 Yes

17 68400 2227 2 4454.142 1.22 Yes

18 66000 315 2.92 920 0.84 Yes

19 30500 2060 2 4120 -16.97 No

22 66800 1800 2 3590 0.62 Yes

24 71000 5350 1.96 10700 0.99 Yes

25 61800 451 2 903 -7.69 Yes

26 64400 3220 2 6440 -0.39 Yes

27 65368 2598 2 5196 -0.12 Yes

28 65800 2830 2 5660 0.04 Yes

29 62052.600 3819.234 3.18 12145.165 -0.95 No

31 56353.985 2817.699 2 5635.399 -3.30 Yes

34 72900 8400 2 16800 0.86 No

35 66600 8320 2 16600 0.11 No


(APLAC T107)


Page 58 of 108

Assigned

Lab No.

Mass Fraction of

Magnesium (mg/kg)

Combined Standard

Uncertainty (mg/kg)

Coverage Factor

k

Expanded

Uncertainty

(mg/kg)

zeta-score Method

Accreditation

36 63400 1520 4.303 6530 -1.48 Yes

37 7.13x104 558 1.96 1.09x103 9.36 Yes

39 65643.369 608.977 2 1217.954 -0.05 Yes

41 75000 9.25 2 18.50 41.60 Yes

42 72200 0.037 2 5342 29.13 Yes

43 69212 3000 2 6000 1.18 Yes

44 80000 0.0053 2 0.0106 63.96 No

46 60300 2200 2 4400 -2.43 No

48 63682 699 2 1398 -2.71 Yes

49 67147 635.889 2 1271.106 2.18 No

50 70862 3550 2 7100 1.46 No

51 59341.55 37.799 2 75.598 -27.88 No

52 66252 8.704 2 17.408 2.58 Yes

53 47373.763 10.518 2 21.036 -81.61 Yes



(APLAC T107)


Page 59 of 108

FIGURE I: Participants’ z-scores for zinc


(APLAC T107)


Page 60 of 108

FIGURE II: Participants’ z-scores for manganese


(APLAC T107)


Page 61 of 108

FIGURE III: Participants’ z-scores for calcium


(APLAC T107)


Page 62 of 108

FIGURE IV: Participants’ z-scores for magnesium


(APLAC T107)


Page 63 of 108

FIGURE V: Participants’ results with their expanded uncertainty for zinc


(APLAC T107)


Page 64 of 108

FIGURE VI: Participants’ results with their expanded uncertainty for manganese


(APLAC T107)


Page 65 of 108

FIGURE VII: Participants’ results with their expanded uncertainty for calcium


(APLAC T107)


Page 66 of 108

FIGURE VIII: Participants’ results with their expanded uncertainty for magnesium


(APLAC T107)


Page 67 of 108

FIGURE IX: Participants’ zeta-scores for zinc


(APLAC T107)


Page 68 of 108

FIGURE X: Participants’ zeta-scores for manganese


(APLAC T107)


Page 69 of 108

FIGURE XI: Participants’ zeta-scores for calcium


(APLAC T107)


Page 70 of 108

FIGURE XII: Participants’ zeta-scores for magnesium


(APLAC T107)


Page 71 of 108

FIGURE XIII: Kernel density plot of zinc


(APLAC T107)


Page 72 of 108

FIGURE XIV: Kernel density plot of manganese


(APLAC T107)


Page 73 of 108

FIGURE XV: Kernel density plot of calcium


(APLAC T107)


Page 74 of 108

FIGURE XVI: Kernel density plot of magnesium


(APLAC T107)


Page 75 of 108

FIGURE XVII. Participants’ results with respect to the digestion techniques for zinc


(APLAC T107)


Page 76 of 108

FIGURE XVIII. Participants’ results with respect to the digestion techniques for manganese


(APLAC T107)


Page 77 of 108

FIGURE XIX. Participants’ results with respect to the digestion techniques for calcium


(APLAC T107)


Page 78 of 108

FIGURE XX. Participants’ results with respect to the digestion techniques for magnesium


(APLAC T107)


Page 79 of 108

FIGURE XXI. Participants’ results with respect to the use of internal standard(s) for zinc


(APLAC T107)


Page 80 of 108

FIGURE XXII. Participants’ results with respect to the use of internal standard(s) for manganese


(APLAC T107)


Page 81 of 108

FIGURE XXIII. Participants’ results with respect to the use of internal standard(s) for calcium


(APLAC T107)


Page 82 of 108

FIGURE XXIV. Participants’ results with respect to the use of internal standard(s) for magnesium


(APLAC T107)


Page 83 of 108

FIGURE XXV. Participants’ results with respect to the analytical instruments for zinc


(APLAC T107)


Page 84 of 108

FIGURE XXVI. Participants’ results with respect to the analytical instruments for manganese


(APLAC T107)


Page 85 of 108

FIGURE XXVII. Participants’ results with respect to the analytical instruments for calcium


(APLAC T107)


Page 86 of 108

FIGURE XXVIII. Participants’ results with respect to the analytical instruments for magnesium


(APLAC T107)


Page 87 of 108

FIGURE XXIX. Participants’ results with respect to the correction for recovery for zinc


(APLAC T107)


Page 88 of 108

FIGURE XXX. Participants’ results with respect to the correction for recovery for manganese


(APLAC T107)


Page 89 of 108

FIGURE XXXI. Participants’ results with respect to the correction for recovery for calcium


(APLAC T107)


Page 90 of 108

FIGURE XXXII. Participants’ results with respect to the correction for recovery for magnesium


(APLAC T107)


Page 91 of 108

FIGURE XXXIII. Participants’ results with respect to the method accreditation status for zinc


(APLAC T107)


Page 92 of 108

FIGURE XXXIV. Participants’ results with respect to the method accreditation status for manganese


(APLAC T107)


Page 93 of 108

FIGURE XXXV. Participants’ results with respect to the method accreditation status for calcium


(APLAC T107)


Page 94 of 108

FIGURE XXXVI. Participants’ results with respect to the method accreditation status for magnesium


(APLAC T107)


Page 95 of 108

APPENDIX I: Homogeneity study

a. The homogeneity study was conducted after the testing material was bottled and

irradiated. 10 bottles of the test material (conditioned at 20 ± 5 C) were randomly

selected from the whole lot of bottles prepared. Two test portions of 0.5 g were taken

from each bottle for analysis.

b. For analysis of zinc, manganese, calcium and magnesium, the test portions were

digested using microwave-assisted acid digestion. Following validated procedures, the

digested samples and method blanks were analysed using standard additions with ICP-

AES.

c. ANOVA technique was applied to assess the between-bottle heterogeneity and the

standard uncertainty originated from the between-bottle heterogeneity was calculated

using the equation (1) given below in accordance with ISO Guide 35:2006 [9.9]. The

results are summarised in below table.

4

within

withinbb

2.

MSνn

MSu (1)

where

ubb: standard uncertainty due to between-bottle heterogeneity

MSwithin: mean square within bottles variance

withinMSν : degree of freedom of MSwithin

n: number of replicates

Summary of homogeneity study results

Measurand

ANOVA test Relative standard uncertainty due to

between-bottle (in)homogeneity,

ubb (%) F-statistics

Critical

value

Zn 1.13 3.02 0.28

Mn 0.74 3.02 0.37

Ca 2.17 3.02 0.23

Mg 1.14 3.02 0.27

d. The homogeneity study results indicated that no significant inhomogeneity was

observed in the test material. The test material was considered fit for the purpose of

APLAC T107.


(APLAC T107)


Page 96 of 108

APPENDIX II: Stability study

a. Long-term and short-term stability studies were conducted for the test material using

the same analytical procedures as for the homogeneity study. The long-term stability

is associated with the behaviour of the test material under storage in participating

laboratories while the short-term stability studies aimed to show the stability of the

material during its transport. The long-term stability was conducted at the storage

temperature (20 ± 5 ºC) using the classical approach covering the period from the

distribution of test material to the deadline for submission of results. The short-term

stability of the food supplement was conducted by randomly selecting and transferring

two bottles of sample stored at the reference temperature (about -20 ºC) to the

simulated transport temperatures (conditioned at 20 ± 5 ºC and 40 ± 5 ºC) on three

occasions (1, 2 and 4 weeks) over the study period. Each bottle of sample was analysed

in duplicate to monitor the sample instability. The stability check was conducted using

an “isochronous” approach that allowed all measurements of the stability study to take

place under repeatability conditions (one run with one calibration).

b. The trend-analysis technique proposed by ISO Guide 35:2006 [9.9] was applied to

assess the stability of the test material at 20 ºC and 40 ºC. The basic model for the

stability study is expressed as the equation (2).

Y = 0 + 1X + (2)

where 0 and 1 are the regression coefficients; and denotes the random error

component. With appropriate t-factors, 1 (slope) can be tested for significance of

deviation from zero. Table below summarizes the results of the stability tests at 20 ºC

and 40 ºC respectively.

Summary of stability study results

Measurand

p-value for the slope

Short-term stability Long-term stability

20 ºC 40 ºC 20 ºC

Zn 0.994 0.701 0.182

Mn 0.253 0.683 0.984

Ca 0.335 0.112 0.088

Mg 0.448 0.790 0.207

c. As all p-values were greater than 0.05, it was concluded that the corresponding slope

was not significantly deviated from zero at 95% level of confidence. In other words,

no instability was observed for the test material at 20 ºC and 40 ºC during the testing

period. The test material was considered fit for the purpose of APLAC T107.


(APLAC T107)


Page 97 of 108

APPENDIX III: Instructions for Participants


(APLAC T107)


Page 98 of 108


(APLAC T107)


Page 99 of 108


(APLAC T107)


Page 100 of 108


(APLAC T107)


Page 101 of 108


(APLAC T107)


Page 102 of 108


(APLAC T107)


Page 103 of 108

APPENDIX IV: Sample Receipt Form


(APLAC T107)


Page 104 of 108

APPENDIX V: Results Proforma


(APLAC T107)


Page 105 of 108


(APLAC T107)


Page 106 of 108


(APLAC T107)


Page 107 of 108


(APLAC T107)


Page 108 of 108

*****End of Report*****

FINAL REPORT APMP-APLAC Joint Proficiency Testing ...

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