ASTM_E_1786_-_08.pdf

Designation:E178608Standard Test Method forDetermination of Low Levels of Water in Liquid Chlorine byOn-Line Infrared Spectrophotometry1This standard is issued under the fixed designation E1786;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 is designed for the on-line determina-tion of the content of water in liquid chlorine in the concen-tration range of 0.5 to 15 mg/kg(ppm).1.2 The values stated in SI units are to be regarded asstandard.The values given in parentheses are for informationonly.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 and Note 3.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterE806 Test Method for Carbon Tetrachloride and Chloroformin Liquid Chlorine by Direct Injection(Gas Chromato-graphic Procedure)2.2 Federal Standards:349 CFR 173 Code of Federal Regulations Title 49 Transpor-tation:Shippers General Requirements for Shipments andPackaging,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 Containers2.3 Other Document:4Chlorine Institute Pamphlet No.77 Sampling LiquidChlorine3.Summary of Test Method3.1 Liquid chlorine continuously flows through a specialinfrared cell where it is maintained as a liquid under its ownpressure.A process infrared spectrometer scans from 400 to4400 wavenumbers of the infrared transmission spectrum ofliquid chlorine.This spectrum then is ratioed to one obtainedfrom the nitrogen-filled infrared cell previously.The ratioedspectrum is converted to absorbance,and the net absorbance ofwater band at 1596 wavenumbers,relative to a reference at1663 wavenumbers,is determined.3.2 The amount of water corresponding to this net absor-bance is determined from a calibration curve prepared from theinfrared absorbencies of standards which contain concentra-tions of water in liquid chlorine.These standards are preparedfrom manual samples of liquid chlorine in tantalum cylinders.Sample from each cylinder is introduced into a calibrationinfrared cell and maintained as a liquid under its own pressure.4.Significance and Use4.1 Trace amounts of water may be detrimental to the use ofchlorine in some applications.The amount of water in thechlorine must be known to prevent problems during its use.5.Apparatus5.1 Process Infrared Spectrometer,capable of measure-ments in the 1600 wavenumber region.An FTIR with fourwavenumber resolution is the instrument of choice,but disper-sive instruments also may be used to achieve similar results.5.2 Special Infrared Calibration Cell(Fig.1),as used forcalibration.Neither cell size nor pathlength are critical to theanalysis,but sensitivity and limit of detection are dependent on1This test method is under the jurisdiction of ASTM Committee E15 onIndustrial and Specialty Chemicals and is the direct responsibility of SubcommitteeE15.02 on Product Standards.Current edition approved April 1,2008.Published May 2008.Originallyapproved in 1996.Last previous edition approved in 2002 as E1786 02.DOI:10.1520/E1786-08.2For 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.3Code of Federal Regulations,available from U.S.Government Printing Office,Washington,DC 20402.4Available from The Chlorine Institute,Inc.,2001 L St.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 pathlength.The concentration range reported in the Section 1 isachievable with a 60-mm pathlength cell constructed with thefollowing:Figs.2-75.2.1 Hastelloy C and 316 Stainless Steel Stock,suitable formachining,5.2.2 Silver Chloride Windows,0.5 cm 2.5 cm,and5.2.3 Perfluoroelastomer Sheet,0.762 mm(0.030 in.)thick-ness.5.3 Ball Valves,Monel 6.35 mm(14-in.)valve with pipe and6.35 mm(14-in.)tube ends.5.4 Needle Valves,Nickel or Monel 6.35 mm(14-in.)valvewith pipe and 6.35 mm(14-in.)tube ends.5.5 Sample Cylinder Assembly(Fig.8),consisting of:5.5.1 Sample Cylinder,nickel,Monel,or tantalum,400 to1000-mL capacity,