1、Designation: D 4856 99 (Reapproved 2004)Standard Test Method forDetermination of Sulfuric Acid Mist in the WorkplaceAtmosphere (Ion Chromatographic)1This standard is issued under the fixed designation D 4856; the number immediately following the designation indicates the year oforiginal adoption or,
2、 in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This ion chromatographic test method describes thedetermination of sulfuric aci
3、d mist in air samples collectedfrom workplace atmospheres in a three-piece cassette filter.1.2 The lower detection limit of this test method is 0.017mg/m3of sulfuric acid (H2SO4) mist in 60 L of air sampled at1 L/min.1.3 This test method is relatively free from interference. Theonly known interferen
4、ce is soluble or partially soluble sulfatesalts.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of reg
5、ulatory limitations prior to use. For specificprecautionary statements, see Section 9.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 1356 Terminology Relating to Sampling and Analysis ofAtmospheresD 1357 Practice for Planning the Sampling of the AmbientAtmosphereD
6、 1605 Practices for SamplingAtmospheres forAnalysis ofGases and Vapors3D 1914 Practice for Conversion Units and Factors Relatingto Sampling and Analysis of AtmospheresD 4327 Test Method for Anions in Water by ChemicallySuppressed Ion ChromatographyE 200 Practice for Preparation, Standardization, and
7、 Stor-age of Standard and Reagent Solutions for ChemicalAnalysis3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology D 1356.3.2 Definitions of Terms Specific to This Standard:3.2.1 eluentionic mobile phase used to transport thesample through the exchang
8、e columns.3.2.2 resolutionability of a column to separate constitu-ents under specified test conditions.4. Summary of Test Method4.1 Aknown volume of air is drawn through a cassette filterholder containing a 37-mm mixed cellulose ester membranefilter of 0.8-m pore size. The filter is held in a 3-pie
9、ce cassettesupported by a cellulose back-up pad.44.2 The filter is desorbed with Specification D 1193 Type 1water and an aliquot of the desorbed sample is injected into anion chromatograph. The sample is pumped through two differ-ent ion exchange columns into a conductivity detector. Thosecolumns ar
10、e a precolumn and separator column which arepacked with low-capacity anion exchanger. Ions are separatedbased on their affinity for the exchange sites of the resin. Amethod for anion suppression is used to reduce backgroundconductivity of the eluent.5. Significance and Use5.1 Sulfuric acid is used i
11、n the manufacture of fertilizer,explosives, dyestuffs, other acids, parchment paper, glue, andthe pickling of metal.5.2 This test method has been found satisfactory for mea-suring sulfuric acid at levels required by federal occupationalhealth regulations.6. Interferences6.1 Soluble or partially solu
12、ble sulfate salts, for example,sodium or calcium sulfate, will constitute a positive bias.7. Apparatus7.1 Sampling Equipment:7.1.1 A 3-piece 37-mm filter cassette constructed of styreneacrylonitrile is used to hold the filter that is supported by a1This test method is under the jurisdiction of ASTM
13、Committee D22 onSampling Analysis of Atmospheres and is the direct responsibility of SubcommitteeD22.04 on Workplace Atmospheres.Current edition approved October 1, 2004. Published December 2004. Originallyapproved in 1988. Last previous edition approved in 1999 as D 4856 - 99e1.2For referenced ASTM
14、 standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Precision (CVT= 0.082) was obtained from NIOSH Contract No. CDC-99-74
15、-45 on a range of 0.561 2.577 mg/M3using cellulose ester filters.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.cellulosic pad. The cassette has polyethylene end plugs that fitinto an inlet and outlet sampling orifice.7.1.2 The filt
16、er that is used in this procedure is a 37-mmdiameter cellulose ester membrane filter of a 0.8-mm pore size.7.1.3 A portable sampling pump capable of a 1 L/minsampling rate with a filter cassette containing a backing padand cellulose ester membrane filter previously described.7.2 Ion Chromatographcap
17、able of delivering 2 to 5 mLofeluent per minute at a pressure of from 200 to 700 psi 1.3 to4.8 MPa.7.2.1 Precolumna column placed before the separatorcolumn to protect it from being fouled by particulate matter.7.2.2 Separator Columna column packed with pellicularanion exchange resin that is suitabl
18、e for resolving the sulfateanion.7.2.3 Suppressor Column or Membranea column packedwith cation exchange resin that is capable of converting theeluent and separated anions to their respective acid forms ormembrane that allows the selective removal of anions.7.2.4 Detectora low-volume, flow through, t
19、emperature-compensated, electrical conductivity cell equipped with ametre capable of reading from 0 to 1 000 S/cm on a linearscale.7.2.5 Recordercompatible with the detector output.7.2.6 Syringeminimum capacity of 2 mL and equippedwith a male pressure fitting.8. Reagents8.1 Reagent-grade chemicals s
20、hall be used in all tests.Unless otherwise indicated, it is intended that all reagents shallconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society, where suchspecifications are available. Other reagents may be usedprovided it can be demonstrated that th
21、ey are of sufficientlyhigh purity to permit the use without decreasing the accuracyof the determination.8.2 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean ultra-pure, Type I wateras described in Specification D 1193.8.3 EluentDissolve 10.080 g of sodium bica
22、rbonate(0.003 M NaHCO3) and 1.0176 g sodium carbonate (0.0024 MNa2CO3) in water and dilute to 4 L with water. Some anionsuppressor membranes use the effluent from the detector. Seemanufacturers guidelines for appropriate use.8.4 Stock Solutions:8.4.1 Sulfate Stock Solution (1.00 mL = 1.00 mg SO42)Dr
23、y sodium sulfate (Na2SO4) for 1 h at 105C and cool indessicator. Dissolve 1.4790 g of dried salt in water and diluteto 1 L with water.8.5 Suppressor Regenerant Solution (for use with suppres-sor columns)Cautiously add 111 mL of concentrated H2SO4(sp gr 1.84) to 600 mL of water. Cool the solution and
24、 dilute to4 L with water. Some anion suppressor membranes use theeffluent from the detector. See manufacturers guidance forappropriate use.8.6 Anion Working SolutionsPrepare a blank and a mini-mum of three different working solutions containing thefollowing concentrations of sulfate. The sulfate sol
25、utions areprepared by diluting the stock solution.8.6.1 High sulfate stock concentration (100 mg/L) is pre-pared by the dilution of 100 mL of the sulfate stock solution to1 000 mL in a volumetric flask with water.8.6.2 Intermediate sulfate stock concentration (10 mg/L) isprepared by the dilution of
26、100 mL of the high stock sulfateconcentration to 1 000 mL in a volumetric flask with water.8.6.3 Low sulfate stock concentration (1 mg/L) is preparedby diluting 100 mL of the intermediate stock sulfate concen-tration to 1 000 mL in a volumetric flask with water.9. Precautions9.1 Safety PrecautionsEx
27、treme care must be taken whenpreparing solutions from concentrated sulfuric acid. The trans-fers should be performed in a fume hood with adequateventilation while wearing the proper safety equipment.9.2 Technical PrecautionsAll storage containers shouldbe plastic such as polyethylene (or polypropyle
28、ne) to preventleaching of the analytes. All connections must be made withnon-metallic materials suitable for use with ion chromato-graphs.10. Sampling10.1 For general information on sampling refer to PracticesD 1357 and D 1605.10.2 Attach the cassette assembly containing the celluloseester filter to
29、 a personal sampling pump using tubing of theproper size as to render a leak proof system and clip thecassette to the workers lapel.10.3 Collect air samples at 1 L/min until a minimum of 40L has been collected.10.4 The cellulose ester filter should be removed from thecassette filter holder within on
30、e hour of sampling and trans-ferred to a screw cap, polyethylene (or polypropylene) bottle.11. Calibration11.1 Determination of Retention Time The retention timefor sulfate anion is determined by injecting a standard solutionand noting the time required for a peak to appear on thechromatogram.11.2 C
31、oncentrations of sulfate are analyzed that encompassthe range of sulfate expected for the samples, (for example, 1to 100 mg/L).11.3 Prepare an analytical curve for sulfate on linear graphpaper using peak height or area versus concentration. Aleast-squares plot of the data should be presented.11.4 A
32、blank should be analyzed of each prepared solutionand used to correct detector response.12. Procedures512.1 Pipet 10 mL of water into the sample bottle containingthe cellulose ester membrane filter. The sample should beshaken and allowed to stand for 10 min prior to filteringthrough medium-porosity,
33、 ashless filter paper such as #40Whatman to remove any undissolved particulate matter.5Consult Test Method D 4327.D 4856 99 (2004)212.2 Transfer a portion of the filtered sample solution to asyringe and inject 2 to 3 mL of the sample entry port of the ionchromatograph that has been set up in accorda
34、nce withmanufacturers instructions.12.3 Determine the amount of sulfate in each sample bycomparing sulfate detector response obtained for each sampleto that obtained on the calibration curve obtained from standardconcentrations.13. Calculation13.1 Calculate the mg/m3of sulfuric acid in air as follow
35、s:mg/m3, sulfuric acid 5g/mLSO43 10 3 1.02La(1)where:g/mL = SO4in water,10 = millilitres of water added to filter,1.02 = conversion factor for sulfuric acid, andLa = litres of air sampled.14. Precision and Bias14.1 The single-operator and overall precision of this testmethod within its designated ra
36、nge for seven operators in sevendifferent laboratories with a 10 mL volume is expressed asfollows:Theoretical, g Observed Standard Deviation, g6.00 1.1360.0 7.7120 17.514.2 Recoveries and bias of known amounts of sulfate inseven different laboratories using the same manufacturersinstrumentation and
37、operation conditions are expressed asfollows:Theoretical,(g)Observed,(g)Bias,(g)Bias,(%)StatisticallySignificant95 % Level6.00 5.07 .93 15.5 Yes60.0 49.1 10.9 18.2 Yes120 97.6 22.4 18.7 Yes15. Keywords15.1 air monitoring; ion chromatographic; sampling andanalysis; sulfuric acid mist; workplace atmos
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41、mmittee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 4856 99 (2004)3
