1、Designation: D4856 11 (Reapproved 2016)Standard Test Method forDetermination of Sulfuric Acid Mist in WorkplaceAtmospheres Collected on Mixed Cellulose Ester Filters (IonChromatographic Analysis)1This standard is issued under the fixed designation D4856; the number immediately following the designat
2、ion indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This ion chromatographic test meth
3、od describes thedetermination of sulfuric acid mist in air samples collectedfrom workplace atmospheres on a mixed cellulose ester (MCE)filter.NOTE 1Other filter types such as quartz fiber, polytetrafluoroethylene(PTFE), and polyvinyl chloride (PVC) filters are also suitable.1.2 The lower detection l
4、imit of this test method is 0.001mg/sample or 0.017 mg/m3of sulfuric acid (H2SO4) mist in 60L of air sampled at 1 L/min.1.3 This test method is subject to interference from solubleand partially soluble sulfate salts. Other sulfur-containingcompounds can be oxidized to sulfate and also interfere.1.4
5、The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 No detailed instrument operating instructions are pro-vided because of differences among various makes and modelsof ion chromatography (IC) systems. Instead, the analyst shallf
6、ollow the instructions provided by the manufacturer of theparticular instrument, analytical column, and suppressors used.1.6 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-p
7、riate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specificprecautionary statements, see Section 9.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1356 Terminology Relating to Sampling and Analysis ofAtmosph
8、eresD1914 Practice for Conversion Units and Factors Relating toSampling and Analysis of AtmospheresD4327 Test Method for Anions in Water by Suppressed IonChromatographyE200 Practice for Preparation, Standardization, and Storageof Standard and Reagent Solutions for Chemical Analysis2.2 ISO and Europe
9、an Standards:ISO 648 Laboratory glasswareOne Mark pipettes3ISO 7708 Air qualityParticle size fraction definitions forhealth-related sampling3ISO 1042 Laboratory glasswareOne-mark volumetricflasks3EN 482 Workplace atmospheresGeneral requirements forthe performance of procedures for the measurement of
10、chemical agents4EN 1540 Workplace atmospheresTerminology4EN 13890 Workplace atmospheresProcedures for measur-ing metals and metalloids in airborne particlesRequirements and test methods43. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology D1356 and EN 1
11、540.3.2 Definitions of Terms Specific to This Standard:3.2.1 eluentionic mobile phase used to transport thesample through the exchange columns.3.2.2 resolutionability of a column to separate constitu-ents under specified test conditions.1This test method is under the jurisdiction of ASTM Committee D
12、22 on AirQuality and is the direct responsibility of Subcommittee D22.04 on Workplace AirQuality.Current edition approved Oct. 1, 2016. Published October 2016. Originallyapproved in 1988. Last previous edition approved in 2011 as D4856 11. DOI:10.1520/D4856-11R16.2For referenced ASTM standards, visi
13、t 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.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York,
14、 NY 10036, http:/www.ansi.org.4Available from European Committee for Standardization (CEN), AvenueMarnix 17, B-1000, Brussels, Belgium, http:/www.cen.eu.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Summary of Test Method4.1 A kn
15、own volume of air is drawn through mixed cellu-lose ester membrane filter-mounted in an appropriate airsampler. Examples are, but not limited to: inhalable samplers,25-mm 3-piece, and 37-mm 3-piece cassettes supported by aback-up pad or screen.54.2 The sulfuric acid collected on the filter is desorb
16、ed withD1193 Type 1 water. An aliquot of the desorbed samplesolution is injected into an ion chromatograph to determine thesulfate ion concentration.5. Significance and Use5.1 Sulfuric acid is used in the manufacture of fertilizer,explosives, dyestuffs, other acids, parchment paper, glue, leadacid b
17、atteries, textiles, etc., and in the pickling of metals.5.2 This test method has been found to be satisfactory in themeasurement of sulfuric acid for comparison with relevantoccupational exposure limits.6. Interferences6.1 Soluble or partially soluble sulfate salts, for example,sodium or calcium sul
18、fate, will be measured as sulfuric acid.Other sulfur-containing compounds can be oxidized to sulfateand also interfere.7. Apparatus7.1 Sampling Equipment:7.1.1 Air sampler designed to collect the appropriate aerosolsize fraction needed. Examples are: inhalable sampler, 3-piece37-mm or 25-mm filter c
19、assette constructed of styrene acrylo-nitrile to hold the filter that is supported by a cellulose pad.7.1.2 A MCE filter.NOTE 2This method may also be used with other appropriate filterssuch PTFE, Glass Fiber, PVC, and others.7.1.3 A personal sampling pump capable of maintaining therequired sampling
20、 rate through the sampler throughout thesampling period.7.2 Ion Chromatograph:7.2.1 Pump, capable of delivering a constant flow of 0.1 to5 mL of eluent per minute at a pressure of from 3.4 to 34 MPa(500 to 5000 psi).7.2.2 Injection Valve, a low dead volume, non-metallicvalve fitted with a sample loo
21、p having a volume of up to 500l, for injecting the samples into the eluent stream. Anautosampler can be attached for automation.7.2.3 Guard Column, a column placed before the separatorcolumn to protect it from being fouled by particulate matter.7.2.4 Separator Column, a column packed with anion ex-c
22、hange resin that is suitable for resolving the sulfate anion.7.2.5 Suppressor Module, a module to reduce the totalconductivity of the eluent, suitable for use with the separatorcolumn and capable of converting the eluent and separatedanions to their respective acid forms.7.2.6 Conductivity Detector,
23、 a low-volume, flow-through,temperature-compensated, electrical conductivity cell.7.2.7 Recorder, Integrator, or Computer, a device for thepurpose of measuring peak height or area, compatible with thedetector output, and capable of recording detector response asa function of time.7.2.8 Eluent Reserv
24、oir, a container suitable for storing aprepared eluent solution.7.2.9 Eluent Generation System, for continuous productionof eluent, suitable for use with the selected separator column,as an alternative to using a manually-prepared eluent.7.2.10 Ultrasonic Bath, preferably with a timer, suitable foru
25、se in the ultrasonic extraction.7.3 Laboratory Supplies:7.3.1 One-mark Volumetric Flasks, capacities between 10mL and 2000 mL.7.3.2 One-mark Pipets, complying with the requirements ofISO 648.7.3.3 Disposable Screw-cap Polyethylene Vessels, of 15-mLcapacity.7.3.4 Disposable Filters, polytetrafluoreth
26、ylene (PTFE),pore size 0.25 m, for use in ion chromatography.7.3.5 Disposable 2-mL or 5-mL Syringes, with Luer lockconnector, for use with disposable filters, or for sampleinjections without an autosampler.7.3.6 Autosampler Vials, suitable for the autosampler used.7.3.7 Pipet Tips, plastic, disposab
27、le, of assorted sizes, asneeded.7.3.8 Labware, preferably plastic (beakers, flasks, graduatedcylinders, etc.), of assorted sizes, as needed.7.3.9 Tweezers, manufactured from plastic or tipped withPTFE, for loading and unloading filters into samplers.8. Reagents8.1 Reagent-grade chemicals shall be us
28、ed 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 used,provided it can be demonstrated that they are of
29、 sufficientlyhigh purity to permit the use without decreasing the accuracyof the determination.8.2 WaterUnless otherwise indicated, reference to watershall be understood to mean ultra-pure, Type I water asdescribed in Specification D1193.8.3 Stock Solutions1000 g/mL (mg/L) sulfate in water.Use a com
30、mercial standard solution with a certified concen-tration traceable to national standards.NOTE 3The sodium carbonate/sodium bicarbonate eluent prescribedbelow is an example that can be used with separator column for thedetermination of sulfate by chemically suppressed ion chromatography.The manufact
31、urers literature will give information on the composition ofeluent to be used with a specific column.8.4 Sodium Carbonate/Sodium Bicarbonate Eluent0.0031Na2CO3and 0.00035 M NaHCO3. Dissolve 0.657 g of anhy-drous Na2CO3and 0.059 g of NaHCO3in a 2000-mL (2-L)volumetric flask with water and dilute to m
32、ark.5Precision (CVT= 0.082) was obtained (NIOSH Contract No. CDC-99-74-45)over a range of 0.561 2.577 mg/M3using mixed cellulose ester filters.D4856 11 (2016)28.5 Eluent Generation CartridgePotassium hydroxide orpotassium carbonate cartridge for eluent generator, appropriatefor column and suppressor
33、 used.8.6 Suppressor Regenerant Solution (for use with suppres-sor columns)Many suppressors currently use electrolysis ofthe eluent for chemical suppression. Refer to manufacturersliterature for the composition of the suppressor regenerationsolution.9. Precautions9.1 Safety PrecautionsExtreme care m
34、ust 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 polypropylene) to preve
35、ntleaching of the analytes. All connections must be made withnon-metallic materials suitable for use with ion chromato-graphs.10. Sampling10.1 Attach the sampler containing the filter to a personalsampling pump using tubing of the appropriate size so as torender a leak-proof system and fasten it to
36、the workers lapel.10.2 Collect air samples at the appropriate flow rate for thesampler until a minimum of 60 L has been collected.10.3 Remove the filter from the sampler within one hour ofsampling and transfer to a screw cap, polyethylene (or poly-propylene) bottle.11. Calibration11.1 Determination
37、of Retention TimeThe retention timefor sulfate anion is determined by injecting a standard solutionand noting the time required for a peak to appear on thechromatogram.11.2 Preparation of Calibration SolutionsUsing the stockstandard solution and water, prepare at least five workingstandards using ap
38、propriate pipettes and volumetric flasks.Standards shall encompass the range of sulfate concentrationsexpected for the samples, (for example, 1 to 100 g/L).11.3 Prepare an analytical curve for sulfate using peakheight or area versus concentration. A least-squares plot of thedata should be presented.
39、11.4 At least one blank of each prepared solution shall beanalyzed.12. Procedures12.1 Pipet 10 mL of water into the sample bottle containingthe filter. Shake the sample bottle vigorously or sonicate it for15 minutes, and allow to stand until the sample solution comesto room temperature.12.2 Filter a
40、n aliquot of the sample solution through adisposable filter (7.3.4) using a disposable syringe (7.3.5).12.3 Set up the IC system for the analysis of sulfate basedon manufacturers literature for the column, suppressor, andsystem used.12.4 Transfer a portion of the filtered sample solution to anautosa
41、mpler vial, or a syringe for manual injections, and injectan aliquot into the chromatograph (for example, 50 L for a4-mm column).NOTE 4Manual injections require 2 to 3 mL to ensure completeflushing of the injection loop.12.5 Determine the amount of sulfate in each sample bycomparing peak area or hei
42、ght to the response obtained fromthe calibration curve determined in 11.3. If sulfate is greaterthan the highest standard, dilute with water and rerun using theappropriate dilution factor.13. Calculation13.1 Calculate the concentration (mg/m3) of sulfuric acid inair as follows:mg/m3,H2SO45g/mL SO431
43、0 31.02Vair(1)where:10 = millilitres of water added to filter,1.02 = conversion factor for H2SO4, from SO4Vair= litres of air sampled.14. Precision and Bias14.1 The single-operator and overall precision of this testmethod, within its designated range for seven operators inseven different laboratorie
44、s with a 10-mL volume, is expressedas follows: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 operation conditions are expressed asfollows:Theoret
45、ical,(g)Observed,(g)Bias,(g)Bias,(%)StatisticallySignificant95 % Level6.00 5.07 0.93 15.5 Yes60.0 49.1 10.9 18.2 Yes120 97.6 22.4 18.7 Yes15. Keywords15.1 air monitoring; ion chromatography; sampling andanalysis; sulfuric acid mist; workplace atmosphereD4856 11 (2016)3ASTM International takes no pos
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