ASTM_D_7550_-_09.pdf

Designation:D755009Standard Test Method forDetermination of Ammonium,Alkali and Alkaline EarthMetals in Hydrogen and Other Cell Feed Gases by IonChromatography1This standard is issued under the fixed designation D7550;the number immediately following the designation 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 test method describes a procedure for the determi-nation of cations in hydrogen and other fuel cell feed gases.Ithas been successfully applied to other types of gaseous samplesincluding air,engine exhaust,and landfill samples.An ionchromatograph/conductivity detector(IC/CD)system is usedto determine cations.Sensitivity from low part per billion(ppb,g/l,g/kg)up to part per million(ppm,mg/l,mg/kg)concentration are achievable dependant on the amount ofhydrogen or other fuel cell gas sampled.This test method canbe applied to other gaseous samples requiring analysis of traceconstituents provided an assessment of potential interferenceshas been accomplished.1.2 The values stated in inch-pound units are to be regardedas standard.No other units of measurement are included in thisstandard.1.3 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 regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent Water3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 densitymass per unit of volume of the fuel gas or airbeing considered.3.1.2 gaseous fuelmaterial to be tested,as sampled,with-out change of composition by drying or otherwise.3.1.3 relative humidityratio of actual pressure of existingwater vapor to maximum possible pressure of water vapor inthe atmosphere at the same temperature,expressed as apercentage.3.1.4 relative densityratio of the density of the gaseousfuel,under the observed conditions of temperature andpressure,to the density of dried air,of normal carbon dioxidecontent(0.03%),at the same temperature and pressure.3.1.5 ion chromatographyliquid chromatographic tech-nique for the rapid separation of ionic species in solution usingion exchange columns and determined using a variety offlow-through detection system most commonly suppressedconductivity.3.1.6 ion chromatograph(IC)Instrument for performingion chromatography.3.1.7 ion conductivity detector(ICD)instrument compo-nent that measures the total change in conductivity of theeluent and analytes flowing between two electrodes.3.1.8 chemical suppressiontechnique using a chemicalreaction to reduce the eluent conductivity and to enhanceanalyte response in ion chromatographic systems using aconductivity detector.3.1.9 electronic suppressiontechnique using an electro-chemical reaction to enhance analyte response in ion chromato-graphic systems using a conductivity detector.3.1.10 eluentsolvent used to transport analytes through anion chromatographic column,suppressor and detector.3.1.11 dscmdry standard cubic meter.4.Summary of Test Method4.1 Hydrogen or other fuel cell gas is passed through ahydrogen quality sampling apparatus containing a calibratedflow meter and a filter module loaded with a nylon filters(1.0m pore size).Alternative sampling apparatus can be usedprovided the fuel cell gas can be accurately measured andcollected free of contamination.When necessary a pump isused to draw sample through the filter module.Filters areremoved from the filter module weighed and extracted intovolumetrically calibrated vessels.The recovered solutions are1This test method is under the jurisdiction ofASTM Committee D03 on GaseousFuels and is the direct responsibility of Subcommittee D03.14 on Hydrogen andFuel Cells.Current edition approved Sept.1,2009.Published October 2009.DOI:10.1520/D7550-09.2For referenced ASTM 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 analyzed for cations using an ion chromatograph/conductivitydetector(IC/CD)system.The cations present elute as peaksfrom the column.The area under the peaks is proportional tothe amount in the sample.The sample amount is measured andcompared to the amount found for standards used to generatea calibration curve.These functions/calculations are mostcommonly performed by chromatography software.5.Significance and Use5.1 Low operating temperature fuel cells such as protonexchange membrane(PEM)fuel cells require high purityhydrogen for maximum material performance and lifeti