silice ulr.pdf

download silice ulr.pdf

of 8

Transcript of silice ulr.pdf

  • 8/10/2019 silice ulr.pdf

    1/8

    Silica

    Page 1 of 8

    Silica, 8282

    How to use instrument-specific information

    The Instrument-specific informationtable displays requirements that may vary between

    instruments. To use this table, select an instrument then read across to find the corresponding

    information required to perform this test.

    Silica DOC316.53.01130Heteropoly Blue Method1

    1 Adapted fromStandard Methods for the Examination of Water and Wastewater.

    Method 8282

    ULR(3 to 1000 g/L as SiO2) Pour-Thru Cell

    Scope and Application: For testing trace levels of soluble silica in pure and ultrapure water

    Test preparation

    Table 383 Instrument-specific information

    Instrument Pour-Thru Kit Cell Orientation Adapter

    DR 6000 LQV175.99.20002 Arrow faces right

    DR 5000 LZV479

    DR 3900LQV157.99.10002 Align cell flow arrows with arrows on cell

    compartment

    DR 3800, DR 2800, DR 27005940400 1-inch (round) path aligned with arrow on

    the adapter

    LZV585 (B)

    Before starting the test:

    See the user manual for Pour-Thru Module installation instructions.

    Clean the Pour-Thru cell and all labware as specified in Labware.

    Protect the Pour-Thru Cell from contamination when not in use by inverting a small beaker over the top of the glass funnel.

    See Reagent preparationfor instructions on preparing the Amino Acid F Reagent.

    The four-minute reaction time in step 10is for samples at 20 C; for samples at 10 C, wait eight minutes; for samples at

    30 C, wait two minutes.

    The one-minute reaction time in step 12is for samples at 20 C; for samples at 10 C, wait two minutes; for samples at

    30 C, wait 30 seconds.

    Make sure the PourThru cell is completely seated in the sample cell compartment.

    Collect the following items:

    Description Quantity

    Amino Acid F Reagent Solution 1 mL

    Citric Acid F Reagent 1 mL

    Molybdate 3 Reagent 1 mL

    Cylinder, graduated, 50-mL, poly 1

    Flask, Erlenmeyer, 250-mL, PMP, with cap 2

    Pipet, TenSette, 0.1 to 1.0 mL with tips 1

    http://doc316.53.01000.pdf/http://doc316.53.01000.pdf/http://doc316.53.01000.pdf/http://doc316.53.01000.pdf/http://doc316.53.01000.pdf/http://doc316.53.01000.pdf/http://doc316.53.01000.pdf/http://doc316.53.01000.pdf/http://doc316.53.01000.pdf/
  • 8/10/2019 silice ulr.pdf

    2/8

    Silica

    Page 2 of 8

    Silica

    See Consumables and replacement itemsfor reorder information.

    Heteropoly Blue method

    1. Select the test.

    Insert an adapter if

    required (see Instrument-

    specific information).

    2. Activate the reagent

    blank option to account forthe Molybdate 3 reagent

    blank. The value is printed

    on the reagent blank.

    3. Use the numeric

    keypad on the instrumentto manually adjust the

    reagent blank value.

    4. Fill two clean 250-mL

    Erlenmeyer flasks tooverflowing with sample.

    5. Fill a clean 50-mL

    plastic graduated cylinder

    with sample from one of

    the flasks; then discard the

    contents of the cylinder.

    Repeat three times.

    6. Fill the rinsed cylinder

    to the 50-mL mark with

    sample from the same

    flask. Discard any

    remaining sample in the

    flask.

    7. Pour the contents of

    the 50-mL cylinder back

    into the original flask.

    8. Repeat steps 5

    through 7for the second

    flask containing sample.

    Collect the following items:

    Description Quantity

    645 Silica ULR

    Stored Programs

    Start

    Reagent Blank

    ON

    Repeat

    Steps 57

  • 8/10/2019 silice ulr.pdf

    3/8

    Silica

    Silica

    Page 3 of 8

    9. Use a TenSettePipet

    to add 1.0 mL of

    Molybdate 3 Reagent to

    each flask. Swirl to mix.

    10. Start the instrument

    timer.

    A four-minute reaction

    period will begin.

    11. When the timer

    expires, add 1.0 mL of

    Citric Acid F Reagent to

    each flask. Swirl to mix.

    12. Start the instrument

    timer.

    A one-minute reaction

    period will begin. The

    destruction of possible

    phosphate interference

    occurs during this period.

    13. When the timer

    expires, pour the contentsof one flask into the

    Pour-Thru Cell.

    14. After the flow stops,

    ZEROthe instrument.

    The display will show:

    0 g/L SiO2

    15. Add 1.0 mL of Amino

    Acid F Reagent to theremaining flask. Swirl to

    mix.

    A faint blue color will

    develop if silica is present.

    16. Wait at least 15

    seconds, then pour thecontents of the second

    flask into the Pour-Thru

    Cell.

    17. READthe results in

    mg/L SiO2.

    18. Flush the Pour-Thru

    Cell with at least 50 mL of

    deionized water

    immediately after use.

    Heteropoly Blue method (continued)

    Zero

    Read

  • 8/10/2019 silice ulr.pdf

    4/8

    Silica

    Page 4 of 8

    Silica

    Interferences

    Table 384 Interfering substances

    Interfering substance Interference level

    Color Eliminated by zeroing the instrument with the blank (follow procedure).

    Iron Interferes at high levels.

    pH (extreme) Adjust pH to less than 7.

    Phosphate (PO43) Interferes at levels greater than 50 mg/L PO4

    3.

    Sulfides Interfere at all levels.

    Turbidity Eliminated by zeroing the instrument with the blank (follow procedure).

  • 8/10/2019 silice ulr.pdf

    5/8

    Silica

    Silica

    Page 5 of 8

    Sample collection, preservation and storage

    Use only plastic containers with tight-fitting closures. Do not use glass containers; they will

    contaminate the sample with silica.

    Soak sampling containers with a solution made of one part Molybdate 3 Reagent to 50 parts of

    high quality deionized water of low silica concentration. Fill the containers completely and let

    stand for several hours. Rinse thoroughly with low-level silica water, drain and close. Repeat

    this cleaning periodically.

    Allow the sample stream to flow for 12 minutes before collection. Do not adjust the flow

    during the sampling period as this may introduce particulates.

    Rinse the container well with sample before collecting the portion for analysis.

    Analyze samples as soon as possible.

    Reagent preparation

    Amino Acid F Reagent Solution is available in either 100-mL bottles or a package of 20 unit-dose

    ampules. The bottled reagent is stable for up to one year if the bottle is kept closed when not in

    use. The ampuled reagent is sealed under argon and is more stable with a shelf life greater than 1

    year. Reduced sensitivity at high concentrations (1000 g/L) indicates reagent instability. Checkthe bottled reagent on a routine basis by performing an analysis on a 1-mg/L (1000 g/L) Silica

    Standard Solution. If the concentration is less than 950 g/L, use a fresh bottle of Amino Acid F

    Reagent Solution.

    Prepare larger or smaller volumes of Amino Acid F Reagent by dissolving Amino Acid F Reagent

    Powder in Amino Acid F Reagent Solvent at a ratio of 11 grams per 100 mL of reagent solvent.

    These reagents are available as the Amino Acid F Reagent Package. This prepared solution has

    limited stability; test routinely with the 1-mg/L Silica Standard Solution.

    Labware

    All containers used in this test must be cleansed thoroughly to remove any traces of silica. Use

    plastic containers for all analysis and storage because glass can contaminate the sample withsilica. Small bottles or flasks with screw-type closures work well.

    1. Clean containers by normal means (do not use phosphate detergents), then rinse with high

    quality deionized water of low-level silica concentration.

    2. Soak for 10 minutes with a 1:50 dilution of Molybdate 3 Reagent in low-level silica water.

    3. Rinse repeatedly with either low-level silica water or the sample before use. Keep containers

    tightly closed when not in use.

    4. Fill the Pour-Thru Cell with this same mixture of Molybdate 3 and water and let stand for

    several minutes before use.

    5. Rinse with low-level silica water.

    Cleaning the Pour-Thru Cell

    The Pour-Thru Cell may accumulate a buildup of colored products, especially if the reacted

    solutions are allowed to stand in the cell for long periods after measurement.

    1. Remove the color by rinsing with a 1:5 dilution of ammonium hydroxide and deionized water.

    2. Rinse several times with deionized water.

    3. Cover the Pour-Thru Cell when it is not in use.

  • 8/10/2019 silice ulr.pdf

    6/8

    Silica

    Page 6 of 8

    Silica

    Accuracy check

    Standard additions method (sample spike)

    Required for accuracy check:

    1-mg/L (1000-g/L) Silica standard

    TenSette Pipet and Pipet tips.

    250-mL plastic Erlenmeyer flasks (3)

    1. After reading test results, leave the sample cell (unspiked sample) in the instrument. Verify the

    chemical form.

    2. Select standard additions from the instrument menu: OPTIONS>MORE>STANDARD

    ADDITION.

    3. Accept the default values for standard concentration, sample volume and spike volumes. After

    the values are accepted, the unspiked sample reading will appear in the top row. See the user

    manual for more information.

    4. Prepare three samples. Fill three plastic Erlenmeyer flasks with 50 mL of prepared sample.

    5. Use the TenSette Pipet to prepare spiked samples: add 0.2 mL, 0.4 mL and 0.6 mL of the1-mg/L standard to each flask and mix thoroughly.

    6. Follow the Heteropoly Blue methodtest procedure for each of the spiked samples, starting

    with the 0.2 mL sample spike. Measure each of the spiked samples in the instrument.

    7. Select GRAPHto view the results. Select IDEAL LINE (or best-fit) to compare the standard

    addition results to the theoretical 100% recovery.

    Standard solution methodNote: Refer to the instrument user manual for specific software navigation instructions.

    Required for accuracy check:

    500-g/L SiO2Standard Solution

    1. Use a 500-g/L SiO2Standard Solution in place of the sample. Follow the Heteropoly Blue

    methodtest procedure.

    2. To adjust the calibration curve using the reading obtained with the standard solution, navigate

    to Standard Adjust in the software: OPTIONS>MORE>STANDARD ADJUST.

    3. Turn on the Standard Adjust feature and accept the displayed concentration. If an alternate

    concentration is used, enter the concentration and adjust the curve to that value.

    Method performance

    Summary of method

    A number of modifications are necessary to adapt the Low Range Silica method for analyzing

    trace levels in the Ultra Low Range method. It is absolutely necessary to use the one-inch Pour-

    Thru Cell and liquid reagents. The Pour-Thru Cell increases the reproducibility of the optics and

    reduces the instability of the readings that result from moveable sample cells. Liquid reagents

    produce more reproducible readings and lower blank values by eliminating slight turbidity that may

    Program Instrument StandardPrecision95% Confidence

    Limits of Distribution

    SensitivityConcentration

    per 0.010 Abs

    645 DR 5000 500 g/L silica 496504 g/L silica 13 g/L silica

  • 8/10/2019 silice ulr.pdf

    7/8

    Silica

    Silica

    Page 7 of 8

    remain when using powdered reagents. Use of liquid reagents in continuous monitors for silica

    provides a means of confirming the analyzer performance.

    Silica and phosphate in the sample react with molybdate ions under acidic conditions to form

    yellow silicomolybdic acid complexes and phosphomolybdic acid complexes. Addition of citric acid

    destroys the phosphate complexes. Amino Acid F Reagent is then added to reduce the yellow

    silicomolybdic acid to an intense blue color, which is proportional to the silica concentration. Test

    results are measured at 815 nm.

    Consumables and replacement items

    Required reagents

    Description Quantity/Test Unit Catalog number

    ULR Silica Reagent Set (using Amino Acid F solution, 100 tests) 2553500

    Includes: (2) 199532, (2) 2254232, (1) 2386442

    ULR Silica Reagent Set (using Amino Acid F ampules, 40 tests) 2581400

    Includes: (1) 199532, (1) 2254232, (2) 2386420

    Amino Acid F Reagent Solution 1.0 mL 100 mL 2386442OR

    Amino Acid F Reagent Solution, 1.2-mL Ampules 1 20/pkg 2386420

    Citric Acid Reagent Solution 2 mL 500 mL 2254249

    Molybdate 3 Reagent Solution 2.0 mL 500 mL 199549

    Required apparatus

    Description Quantity Unit Catalog number

    Cylinder, graduated, 50-mL, poly 1 each 108141

    Flask, Erlenmeyer, 250-mL, PMP, w/cap 2 each 2089846

    Pipet, TenSette, 0.1 to 1.0 mL 1 each 1970001

    Pipet Tips, for TenSette Pipet 19700-01 5 50/pkg 2185696

    Recommended standards

    Description Unit Catalog number

    Silica Standard Solution, 1-mg/L SiO2 500 mL 110649

    Silica Standard Solution, 500-g/L SiO2 3.78 L 2100817

    Water, deionized 4 L 27256

    http://www.hach.com/hc/search.product.details.invoker/PackagingCode=2553500http://www.hach.com/hc/search.product.details.invoker/PackagingCode=2581400http://www.hach.com/hc/search.product.details.invoker/PackagingCode=2386442http://www.hach.com/hc/search.product.details.invoker/PackagingCode=2386420http://www.hach.com/hc/search.product.details.invoker/PackagingCode=2254249http://www.hach.com/hc/search.product.details.invoker/PackagingCode=199549http://www.hach.com/hc/search.product.details.invoker/PackagingCode=199549http://www.hach.com/hc/search.product.details.invoker/PackagingCode=2254249http://www.hach.com/hc/search.product.details.invoker/PackagingCode=2386420http://www.hach.com/hc/search.product.details.invoker/PackagingCode=2386442http://www.hach.com/hc/search.product.details.invoker/PackagingCode=2581400http://www.hach.com/hc/search.product.details.invoker/PackagingCode=2553500
  • 8/10/2019 silice ulr.pdf

    8/8

    HACH COMPANYWORLD HEADQUARTERSTelephone: (970) 669-3050

    FAX: (970) 669-2932

    FOR TECHNICAL ASSISTANCE, PRICE INFORMATION AND ORDERING:Call 800-227-4224

    Contact the HACH office or distributor serving you.

    www.hach.com [email protected]

    In the U.S.A.

    Outside the U.S.A.

    On the Worldwide Web ; E-mail

    toll-free

    Hach Company, 2007, 2010, 2012. All rights reserved. Printed in the U.S.A. Edition 7

    Optional reagents and apparatus

    Description Unit Catalog number

    Ammonium Hydroxide, 58% 500 mL 10649

    Molybdate 3 Reagent 2.9 L 199503

    Molybdate 3 Reagent 3.78 L 199517

    Molybdate 3 Reagent 100 mL 199532

    Molybdate 3 Reagent 1 L 199553

    PourRiteampule breaker each 2484600

    Amino Acid F reagent package each 2254117

    Sampling Bottle with cap, low density polyethylene, 500 mL 12/pkg 2087079

    Thermometer, Non-Mercury, -10 to 225 C each 2635700