ASTM_E_1746_-_08.pdf

Designation:E174608Standard Test Method forSampling and Analysis of Liquid Chlorine for GaseousImpurities1This standard is issued under the fixed designation E1746;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.Scope*1.1 This test method covers sampling and analysis of liquidchlorine for the determination of oxygen(200 to 400 g/g),nitrogen(400 to 800 g/g),and carbon dioxide(800 to 1000ppm)content at levels normally seen in liquid chlorine.Hydrogen and carbon monoxide concentrations in liquid chlo-rine are typically at or below the detection limit of this testmethod.NOTE1The minimum detection limit of hydrogen using a 1 cm3gassample and argon carrier gas is 100 to 200 g/g.2The detection limit forthe other components is significantly lower.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 Review the current Material Safety Data Sheets(MSDS)for detailed information concerning toxicity,first aidprocedures,and safety precautions.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 regulatory limitations prior to use.Specific hazardsstatements are given in Section 7.2.Referenced Documents2.1 Code of Federal Regulations:349 CFR 173,Code of Federal Regulations Title 49,Trans-portation:Shippers General Requirements for Shipmentsand Packaging,including the following sections:173.304 Charging of Cylinders with Liquefied CompressedGas173.314 Requirements for Compressed Gases in Tank Cars173.315 Compressed Gases in Cargo Tanks and PortableTank Containers2.2 Other Document:Chlorine Institute Pamphlet No.77 Sampling Liquid Chlo-rine43.Summary of Test Method3.1 Asample of liquid chlorine is trapped in a sampling tubeand vaporized into a steel bomb.The vaporized chlorine in thesteel bomb is introduced into a gas chromatograph by a gassampling loop(1 cm3)using a ten-port gas sampling andswitching valve.The separations are made on a Porapak Qcolumn and on a 5Amolecular sieve column whose lengths aresuch that the peaks do not overlap.3.2 Any component that co-elutes with the components ofinterest may interfere with this analysis.4.Significance and Use4.1 It is very difficult to exclude sample contamination byambient air during the process of sampling.The levels ofatmospheric contamination caused by poor sampling methodsare often equal to or larger than the levels of the gaseousimpurities present in the chlorine.This results in markedlyelevated levels of detected impurities.As specifications be-come tighter,it becomes more important to measure thegaseous impurity levels in liquid chlorine correctly.4.2 Additional problems are experienced in the sampling ofliquefied gases for the gaseous impurities.The gaseous impu-rities reach an equilibrium between the liquid phase and vaporphase in a sample bomb.The quantity of gases measured in anyparticular sample containing both liquid and vapor will be afunction of the amount of vapor space in the sample bomb.This test method avoids the presence of liquid in the samplebomb.5.Apparatus5.1 Gas ChromatographShimadzu GC-8AIT equipped asshown in Fig.1,or equivalent,equipped with a thermalconductivity detector.1This test method is under the jurisdiction of ASTM Committee E15 onIndustrial and Specialty Chemicalsand is the direct responsibility of SubcommitteeE15.02 on Product Standards.Current edition approved Dec.15,2008.Published January 2009.Originallyapproved in 1995.Last previous edition approved in 2001 as E1746-95(2001)1.DOI:10.1520/E1746-08.2Thompson,B.,Fundamentals of Gas Chromatography,Varian InstrumentsDivision,Sunnyvale,CA,p.73.3Available from Standardization Documents Order Desk,Bldg.4 Section D,700Robbins Ave.,Philadelphia,PA 19111-5094,Attn:NPODS.4Available from The Chlorine Institute,Inc.,2001 LStreet NW,Washington,DC20036-4919.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.2 Recorder,1 mV,0.5 s full-scale response.5.3 Valve Sequencer and Actuator,for switching valvecontrol.5.4 Switching Valves.5.4.1 Ten-Port Switching and Sampling Valve(stainlesssteel is acceptable).5.4.2 Four-Port Switching Valve(stainless steel is accept-able).5.5 Chromatographic Columns,3.2-mm outside diameter,316 stainless,as follows:5.5.1 2 m of 80/100 mesh Porapak N,55.5.2 0.8 m of 80/100 mesh Shimalite Q,65.5.3 1 m of 80/100 mesh Shimalite Q,65.5.4 0.8 m of 80/100 mesh Shimalite Q,65.5.5 3 m of 45/60 mesh molecular sieve 5A,5.5.6 2 m of 80/100 mesh Porapak Q,55.5.7 2 m