The determination of non-intentionally added substances (NIAS) … · 2019. 3. 11. ·...
Transcript of The determination of non-intentionally added substances (NIAS) … · 2019. 3. 11. ·...
The determination of
non-intentionally added substances (NIAS)
as a part of ‘safety-by-design’
Date: July 2016, Version 1
Fera Science Ltd
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• To be the global provider of leading edge scientific solutions,
evidence and advice across the agri-food chain.
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authenticity
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Crop health protection
Targeted knowledge for
informed decision making
Targeted knowledge for
informed decision making
Food packaging &
migration
Food packaging &
migration
Novel foodstuffs
Novel foodstuffs
From Farm to ForkFrom Farm to Fork
What can migrate from FCMs?
• Known ingredients such as monomers, catalysts, solvents,
suspension media, additives etc.
• Known or unknown isomers, oligomers (arguable if NIAS or
not), impurities, reaction products and breakdown
products of these ingredients
• Possible contaminants from the manufacturing process
such as recycled materials, irradiated products etc
• Contamination from indirect sources such as printing inks,
external coatings, adhesives, secondary packaging
IAS
NIAS
EU legislation - NIAS
• Framework Regulation EC 1935/2004 Article 3 and Plastics
Regulation EU 10/2011 Article 19
• FCM manufacturers are obliged to ensure the safety of their
products
• Safety of NIAS must be assessed
• Presently, there are no levels of migration or exposure set
for which compliance with this requirement can be
demonstrated
• EU 10/2011 states unauthorised substances may be used in
FCM plastics, provided they do not migrate at levels above
10 µg/kg food, and this is often used for NIAS
Protocols to follow……
• Presently no legally prescriptive guidelines on how to
assess the safety of NIAS
• ILSI Monograph - Guidance on best practices on the risk assessment
of NIAS in Food Contact Materials and Articles (July 2015)
• What approach should be taken?
Reporting
Data interpretation
Analysis
Extraction or migration exposure
Sample preparation
Initial discussions
Targeted vs. Non-targeted analysis
Specific extractionClean-up
Specific analysis
Generic extraction
Minimal clean-upGeneric analysis
IAS - Know exactly what to measure
PredictableNIAS – oligomers,
impurities, literature references
NIAS -Complete unknowns
Targeted Non-targeted
Analysis and Data interpretation
Reporting
Data interpretation
Analysis
Extraction or migration exposure
Sample preparation
Initial discussions
Identification
Quantification
0 50 100
NM
R in
teg
ral v
alu
e
Concentration
TIC vs. EIC?
vs.
Detection
Detection of NIAS
• Is chromatography required?
• Ambient mass spectrometry - rapid diagnostic information
PVC gasket
Atmospheric pressure Solids Analysis Probe (ASAP)
Driffield et al. (2015) Use of ASAP-TOF-MS to screen for plasticisers in gaskets used in contact with foods. Rapid Communications in Mass Spectrometry, 29,
1603-1610.
Direct Analysis in Real Time (DART)
HR-MS
Real time chemical imaging of the surface
FCM
Identification of NIAS – GC-MS
• Volatile and semi-volatile NIAS - GC-MS
• Identification can be carried out by comparison to
electron impact (EI) MS libraries
• Libraries contain many 10,000’s of substances but often still
unknown NIAS with no library match
(replib) Decane
30 60 90 120 150 180 210 240 270 300 330 360 390 4200
50
100
30
43
57
71
85
99113 142
n-decane
NO LIBRARY MATCH
GC-MS (EI) TIC of FCM solvent extract
GC-MS (chemical ionisation)
• Electron impact – high energy, leads to fragmentation
• Chemical ionisation – softer ionisation which can lead to
quasi-molecular species (or higher mass fragments)
• Different mechanisms possible, e.g. proton transfer
e-. + M → M+. + 2e-→ F1+. + F2 →→
e-. + CH4 → CH4+. + 2e-
CH4+. + CH4 → CH5
+ + CH3.
CH5+ + M → CH4 + [M+H]+
GC-MS EI vs. NCI for Triacetin
(mainlib) Triacetin
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 2300
50
100
1527 32
43
61 73 86
103
116
145
158
O O
O
O
O
O EI-MS(library)
NCI-MS
OO
O
O
CH3
CH3
O
CH3
O TriacetinMW 218
[M-H]-
EI = Electron impact ionisationNCI = Negative chemical ionisation
GC-TOF-MS
• High resolution – higher selectivity
• Accurate mass – potential chemical formulae for
fragments (molecular adduct if using chemical ionisation)
• Some accurate mass libraries available but not as
comprehensive as EI libraries
OH+
O
O
= C8H5O3+ = 149.0250
GC-TOF-MS – FCM extract
OH+
O
O
= C8H5O3+ = 149.0250
EICs at m/z 149.0250 with different mass windows
TIC
m/z 148.5250-149.5250+/- 3300 ppm
m/z 148.9877-149.0623+/- 250 ppm
m/z 149.0213-149.0287+/- 25 ppm
Identification of NIAS – LC-MS
• Non-volatile and polar NIAS detected by LC-MS
• Liquid chromatography
• Reversed phase – typically used for LC-MS
• HILIC – smaller, very polar and/or basic analytes
• HR-MS
• Accurate mass, isotope information (spacing and intensity),
fragmentation (in-source or MS/MS)
• Positive and negative ionisation modes possible
Database searching
• Comparison of list of accurate masses to theoretical
database
• Can include retention time, structures, MS/MS fragment data
• Theoretical oligomers and reaction products associated with
starting materials (and impurities if known) below 1000 Da
• Should consider simulant-oligomer interactions
• Can contain tens of thousands of compounds….
• Not confirmed unless compared to authentic standard
AA TMA PA CHDM BD EG DEG PG HD HMP TMP NPG H2O MWPA+EG linear 1 1 1 210.0528EG+PA+EG linear 1 2 2 254.0790PA+EG+PA+EG linear 2 2 3 402.0951PA+EG+PA+EG cyclic 2 2 4 384.0845PA+EG+PA+EG+PA linear 3 2 4 550.1111PA+EG+PA+EG+PA+NPG linear 3 2 1 5 636.1843PA+EG+PA+NPG+PA+EG linear 3 2 1 5 636.1843PA+PG+PA+PG+PA+PG linear 3 3 5 636.1843PA+PG+PA+PG+PA+PG cyclic 3 3 6 618.1737
Halogenated-oligomers
• Identified by isotope pattern
• M:M+2 3:1 intensity = Cl
• M:M+2 1:1 intensity = Br
• Predicted formulae can indicate presence of multi-halogenated oligomers
• F is monoisotopic but presence of F atoms indicated by massdeficient masses
• If monomer contains 5xF atoms then presence of substances inGC-MS or LC-MS analysis containing 5xF, 10xF, 15xF, 20xF etcmight indicate oligomer
• Other multiples of F indicate reaction and/or breakdownproducts
• How do we differentiate between linear and cyclic
oligomers?
• Authentic standards available?
• Chromatography
• Retention time differences?
• Structural isomers?
• Functional group specific chemistry
Linear or cyclic oligomers?
BADGE.BPA = C36H40O6Cyclo-di-BADGE = C36H40O6
R
O CH3 O CH3
O O
+ no reaction
R
O F3C O CF3
O O
+
R
O
O
F3C
O
CF3
O
Acylation reactions
Driffield et al. Agilent Application Note: LC-TOF-MS as a tool to support can coating/food interaction studies
LC-QTOF-MS investigation
• Can we use MS data to differentiate between linear and
cyclic oligomers?
• Accurate mass information will be the same
• BADGE.BPA = C36H40O6, Cyclo-di-BADGE = C36H40O6
• Fragment ions characteristic of the presence of an epoxy
group?
C+
O
O
CH3
CH3
C12H15O2+
m/z 191.1067C+
OH
CH3
CH3
C9H11O+
m/z 135.0804 C+
O
CH3
CH3
OH
OH
C12H17O3+
m/z 209.1172
FCM with oligomers – cyclic or linear?
LC-QTOF-MS EIC at m/z 404.2430Database hit to potential oligomer
C+
OH
CH3
CH3
C+
OH
CH3
CH3
C+
OH
CH3
CH3
C+
O
O
CH3
CH3
C+
O
O
CH3
CH3
135.0801
Quantification
• How can we quantify if we don’t know what we are looking
for?
• Internal standards
• 2H, 13C analogues – not naturally occurring
• Range of compounds to cover the mass range of interest?
• IS that responds in positive and negative ionisation (for LC-MS)
• External standards
• Chemically similar to substances of interest
e.g. BADGE or BADGE hydrolysis products for epoxy-related
e.g. Polyester diol urethane substance for polyester-related
• Synthesis of authentic standards to confirm identity
• Retention time, accurate mass, fragmentation comparison
• Expensive and time consuming
Quantification by LC-TOF-MS and NMR
Extraction of a FCM with solvent
AA TMA PA CHDM BD EG DEG PG HD HMP TMP NPG H2O MWPA+EG linear 1 1 1 210.0528EG+PA+EG linear 1 2 2 254.0790PA+EG+PA+EG linear 2 2 3 402.0951PA+EG+PA+EG cyclic 2 2 4 384.0845PA+EG+PA+EG+PA linear 3 2 4 550.1111PA+EG+PA+EG+PA+NPG linear 3 2 1 5 636.1843PA+EG+PA+NPG+PA+EG linear 3 2 1 5 636.1843PA+PG+PA+PG+PA+PG linear 3 3 5 636.1843PA+PG+PA+PG+PA+PG cyclic 3 3 6 618.1737
0 50 100
NM
R in
teg
ral v
alu
e
Concentration
0.04 mg/6 dm2
0.03 mg/6 dm2Monomer functional group quantification
Oligomer determination
0
20
40
60
80
100
120
0 50 100 150
Are
a
Concentration
Quantification by LC-TOF-MS and NMR
• Taking into account the uncertainties associated with
each of the measurement techniques, these results are in
fact very similar
• NMR measures actual epoxy functionality, whereas the
epoxy structures by LC-TOF-MS are assumed and not
confirmed by comparison to authentic standards
• Concluded that there is 0.03 mg/6 dm2 of residual epoxy
functionality in the acetonitrile extract of the FCM
Universal detectors
• Chromatography detector where the response is independent of chemical structure
• For example GC-FID, LC-ELSD, LC-CAD
• Rely on the separation capability of chromatography as not as selective as MS detectors
• Must have good separation of NIAS in chromatogram – not usually the case
• Testing of real food samples difficult as components from food may interfere
• Still need a decision in consultation with customer on which standard(s) will be used for quantification
NIAS and ‘safety-by-design’
• Close relationship between Manufacturer of FCM and
Analytical Laboratory allows an iterative process during
new product development
• Better understanding of components of ingredients should
lead to more ‘predictable’ NIAS
• What is the effect of changing an ingredient or processing
temperature to the profile of the NIAS?
Summary
• Ever-advancing analytical instrumentation provides very
powerful tools for determination of IAS and NIAS
• As instruments become more readily available and
sensitivity increases there is the potential for more and
more NIAS to be detected
• Identification and quantification are still providing
challenges
• Evolution of current technologies to be used in new areas or
to provide different information, but also evolution of new
technologies to be used in NIAS determination
Acknowledgements
• Julie Christy
• Antony Lloyd
• Mónica García-López
• Jonathan Tarbin
• James Donarski
• Emma Bradley
• Laurence Castle