1、Designation: E 2036 07Standard Test Method forNitrogen Trichloride in Liquid Chlorine by High PerformanceLiquid Chromatography (HPLC)1This standard is issued under the fixed designation E 2036; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 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. Scope*1.1 This test method uses high performance liquid chroma-tography (HPLC) to determine nitrogen tr
3、ichloride levels inliquid chlorine at the 0.1 to 600 g/g (ppm) range. Solventsamples from chlorine production facilities containing veryhigh concentrations of nitrogen trichloride may be analyzed bydilution with methanol.1.2 The values stated in SI units are to be regarded asstandard. The values giv
4、en in parentheses are for informationonly.1.3 Review the current material safety data sheet (MSDS)for detailed information concerning toxicity, first aid proce-dures, and safety precautions.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It i
5、s 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 hazardstatements are given in Section 8.2. Referenced Documents2.1 ASTM Standards:2E 180 Practice for Determining t
6、he Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty ChemicalsE 806 Test Method for Carbon Tetrachloride and Chloro-form in Liquid Chlorine by Direct Injection (Gas Chro-matographic Procedure)2.2 Federal Standard:3CFR 173 Title 49 Transportation; Shippers General Re-quir
7、ements for Shipments and Packaging, including Sec-tions:173.304 Charging of Cylinders with Liquified Com-pressed Gas173.314 Requirements for Compressed Gases in TankCars173.315 Compressed Gases in Cargo Tanks and PortableTank Containers2.3 Other Document:Chlorine Institute Pamphlet No. 77 Sampling L
8、iquid Chlo-rine43. Summary of Test Method3.1 Weighed samples of chlorine are delivered into a cooledgraduated centrifuge tube. One mL of cooled HPLC eluent isadded before the chlorine is allowed to evaporate. After thechlorine has evaporated the remaining eluent is analyzeddirectly on the HPLC for n
9、itrogen trichloride concentration.3.2 In-process solvent samples from chlorine productionfacility may be analyzed by dilution in methanol followed bydirect HPLC analysis of the diluted solution.4. Significance and Use4.1 This test method was developed for the determination ofnitrogen trichloride in
10、samples of carbon tetrachloride liquidtaken from the compressor suction chiller bottoms of chlorineproduction plants and other places in the plants that may collectand concentrate nitrogen trichloride to levels that could ex-plode. The test method was then modified to measure the lowerlevels of nitr
11、ogen trichloride observed in product liquid chlo-rine. This test method is sensitive enough to measure the levelsof nitrogen trichloride observed in the normal production ofliquid chlorine.4.2 This test method for nitrogen trichloride will require thedilution (100:1) of highly concentrated in-proces
12、s samples tobring them within the working range of the analysis.5. Interferences5.1 This test method is selective for nitrogen trichloride. Atthis time there is no known interference in the materials usedin this test method.1This test method is under the jurisdiction of ASTM Committee E15 onIndustri
13、al and Specialty Chemicals and is the direct responsibility of SubcommitteeE15.02 on Product Standards.Current edition approved April 1, 2007. Published May 2007. Originallyapproved in 1999. Last previous edition approved in 2001 as E 2036 - 01.2For referenced ASTM standards, visit the ASTM website,
14、 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 U.S. Government Printing Office, Superintendent of Docu-ments, Washington, DC 20402.4Available from
15、The Chlorine Institute Inc., 70 W. 40thSt., New York, NY10018.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 Contact with any metal surfaces should be avoided due
16、to the corrosive nature of the sample.5.3 Nitrogen trichloride is decomposed by UV light, heat orstrong acid. The presence of metal ions will increase the rate ofdecomposition. Special care should be taken to avoid exposureof the samples to direct sunlight. Samples and standards shouldbe analyzed im
17、mediately upon preparation. Samples not im-mediately analyzed must be stored in dry ice until just beforeanalysis.6. Apparatus6.1 Ahigh performance liquid chromatograph (HPLC) com-posed of the following:6.1.1 HPLC Pump, capable of 1 mL/min flow,6.1.2 HPLC UV Detector, capable of operating at 221 nmw
18、ith a 1-cm light path,6.1.3 HPLC Injection Valve, 20 L sample loop, all non-metal, and6.1.4 HPLC Column, C18 reverse phase, 25 cm by 4.6 mm.6.2 Plastic Syringes. 1, 2, 5, 10, 20, and 60 mL.6.3 Nonmetallic Syringe Needles.6.4 Top Loader Balance, capable of 0.01 g resolution and 1kg capacity.6.5 TFE-f
19、luorocarbon Tubing, 1.59 mm outside diameter.6.6 Stainless Steel Sample Cylinder, with a needle valve onone end.6.7 Graduated Centrifuge Tube,15mL.6.8 Reducing Tube Fitting, 6.35 mm to 1.59 mm tubing.7. Reagents7.1 Purity of ReagentsUnless otherwise indicated, it isintended that all reagents shall c
20、onform to the specifications ofthe Committee onAnalytical Reagents of theAmerican Chemi-cal Society, where such specifications are available.5Othergrades may be used, provided it is first ascertained that thereagent is of sufficiently high purity to permit its use withoutlessening the accuracy of th
21、e determination.7.2 Water, HPLC grade.7.3 Methanol, HPLC grade.7.4 Sodium Acetate, reagent grade.7.5 Glacial Acetic Acid, reagent grade.7.6 Dry Ice.7.7 Ammonium Sulfate, reagent grade.7.8 Chlorine, reagent grade.7.9 Helium.8. Hazards8.1 Safety and Health PrecautionsExposure to all sol-vents used in
22、this test method should be avoided.8.2 Concentrations of nitrogen chloride over 2 % pose therisk of explosion and should be considered dangerous. Neverallow any solutions containing nitrogen chloride to evaporate,concentrating the nitrogen chloride in the remaining residue.The concentrations of nitr
23、ogen trichloride synthesized in thistest method are small and should not pose any significant riskof explosion. All of the solutions prepared in this test methodcan be disposed of by flushing them down any laboratory sinkusing a reasonable amount of water.8.3 Chlorine is a corrosive and toxic materi
24、al. A well-ventilated fume hood should be used to house all samplehandling and to vent the test equipment when this product isanalyzed in the laboratory.8.4 This analysis should only be performed by persons whoare thoroughly familiar with the handling of chlorine, and evenan experienced person shoul
25、d not work alone. The operatormust be provided with adequate eye protection and a respirator.Splashes of liquid chlorine destroy clothing and, if suchclothing is next to the skin, will produce irritations and burns.8.5 If liquid samples are to be taken in cylinders, do notallow the sample cylinder t
26、o become liquid full. Test MethodE 806, 49 CFR 173.314, 173.315, and 173.304 advise that theweight of the chlorine in the cylinder should not be more than125 % of the weight of the water that the cylinder couldcontain.8.6 When sampling and working with chlorine out-of-doors,people downwind from such
27、 an operation should be warned ofthe possible release of chlorine vapors.8.7 In the event chlorine is inhaled, first aid should besummoned immediately and oxygen administered withoutdelay.8.8 Store pressurized samples where involuntary releasewould not cause excessive risk to people or property.8.9
28、It is recommended that means be available for disposalof excess chlorine in an environmentally safe and acceptablemanner. If chlorine cannot be disposed of in a chlorineconsuming process, a chlorine absorption system should beprovided. When the analysis and sampling regimen requires aninitial purgin
29、g of chlorine from a container, the purged chlorineshould be similarly handled. Purging to the atmosphere shouldbe avoided.9. Typical Instrument Parameters9.1 Adjust the chromatograph in accordance with the fol-lowing parameters and allow the instrument to equilibrate untila steady baseline is obtai
30、ned:9.1.1 ColumnC18 reverse phase ODS (C18) 25 cm by 4.6mm, 10 m,9.1.2 Eluent60 % by volume methanol, 40 % by volume0.1 mol/L (M) acetate buffer, pH 4.5, helium sparged,9.1.3 Flow Rate1 mL/min,9.1.4 Injection Volume20-l sample loop, and9.1.5 Detector WavelengthUV at 221 nm.10. Preparation of Buffer
31、Solution10.1 Sodium Acetate Buffer Stock Solution (1 mol/L (M)Dissolve 136 g sodium acetate (NaOOCCH33 3H2O) and 60 gglacial acetic acid (HOOCCH3) in water and dilute to 1 L.10.2 Sodium Acetate Buffer (0.1 mol/L (M)Transfer 100mL of the stock buffer solution into a 1-L volumetric flask anddilute to
32、volume with water.5Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the Unite
33、d States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.E203607211. Preparation of Eluent11.1 Add 600 mLmethanol to 400 mL0.1 M sodium acetatebuffer solution and mix well. Before use purge the solutionwith helium for 20 min to remove dissolved oxygen.12.
34、 Preparation of the Sample Cylinder12.1 Clamp the sample cylinder in a vertical position withthe needle valve in the downward position. Insert the 6.35 mmend of the reducing tube fitting into the needle valve and set the6.35 mm nut and ferrule of the fitting. Insert the 1.59 mmfluoropolymer tubing i
35、n the reducing tube fitting and tightenthe 1.59 mm nut and ferrule. See Fig. 1. It may be helpful to cuta 6.35 mm circle of fluoropolymer frit material and place it intothe reducing fitting prior to assembly to prevent plugging of the1.59 mm tubing. Cut the length of the 1.59 mm tubing so thatonly 3
36、8.10 mm protrudes out of the fitting.13. Standardization of the HPLC13.1 Prepare a 1000-g/g (ppm) stock solution of ammo-nium sulfate in water. Make a series of standards of ammoniumsulfate by serial dilution covering the range between 1 and 650g/g (ppm) nitrogen trichloride. Calculate the nitrogen
37、trichlo-ride concentration of each standard from the ammonium sulfateconcentration by multiplying by the ratio of the molecularweights, as follows:2NCl3/NH4!2SO4#52 3 120.5/132!51.826 (1)13.2 Withdraw 0.5 mL of an ammonium sulfate standardinto a 1-mL plastic syringe and then pull the plunger back to
38、the 1-mL mark to fill the remainder of the syringe with air.13.3 Clamp a sample cylinder containing reagent chlorinevertically in a ring stand and attach a 152.4 mm piece of 1.59mm outside diameter fluoropolymer tubing to the valve. Takea second 1-mL plastic syringe and pull the plunger back to the1
39、-mL mark. Insert the 1.59 mm fluoropolymer tubing into thesecond syringe and gently purge chlorine through the syringefilling this second syringe with reagent chlorine gas. Removethe fluoropolymer tubing from the syringe and attach anonmetal needle to the luer tip.13.4 Holding the first syringe poin
40、ted upward, use thesecond syringe equipped with the nonmetal needle to bubblethe reagent chlorine gas through the ammonium sulfate stan-dard solution, converting the ammonium ions to nitrogentrichloride. Use of a 1-mL syringe should avoid overchlorina-tion. See Fig. 2.13.5 Use the entire 0.5 mL stan
41、dard to flush the samplevalve and fill the sample loop. Immediately inject this standardinto the HPLC for analysis. The nitrogen trichloride peak willelute between 11 and 12 min in the chromatogram. See Fig. 3.13.6 Measure and record the peak height of the nitrogentrichloride peak in the analysis of
42、 each of the standardsolutions. Plot the peak heights of each standard versus theconcentrations of the nitrogen trichloride in each standardanalyzed. The slope and intercept of this line will be used in thecalculation of the sample analysis values. See Figs. 4 and 5.NOTE 1Standards over 200 g/g (ppm
43、) require 2 mL of chlorine gasfor complete conversion of the ammonium ions to nitrogen trichloride. Ifthe calibration curve is extended beyond 650 g/g (ppm), more than 2 mLof reagent chlorine gas may be needed to obtain complete conversion ofthe ammonium ions in the standards. Although the amount of
44、 chlorineused for the chlorination of the standards is extremely small whencompared to that of the sample, it is always a good idea to prepare the firststandard in any calibration curve without the addition of the ammoniumsulfate to serve as a reagent blank.NOTE 2Two calibrations, one completed in D
45、ecember 1995 and onecompleted in February 1996, were not significantly different. This wouldindicate considerable stability of the UV detector. Considering the easewith which this test method can be calibrated, a one-point check of thecalibration curve is recommended on a weekly basis to ensure that
46、 thesystem is working properly.14. Procedure for Liquid Chlorine14.1 Tare a metal sample cylinder equipped with a needlevalve and cool the cylinder in dry ice making sure that theneedle valve is closed. Sample the liquid chlorine source usingmetal tubing pipe connections. Do not use fluoropolymer or
47、other type of plastic tubing that could transmit UV light.Nitrogen trichloride is very rapidly decomposed in the pres-ence of UV light. Consult the Chlorine Institute Pamphlet No.77 for specific details involved in the sampling of liquidchlorine.14.2 Re-weigh the sample cylinder to determine the wei
48、ghtof chlorine collected in the cylinder before the cylinder isallowed to warm. If the cylinder is more than 60 % full, drainsome of the liquid chlorine out of the bottom of the cylinderand reweigh until the weight of the chlorine is within accept-able limits for that cylinder.NOTE 3For example, a 1
49、50-mL cylinder should not contain more than90 mL of chlorine at a density of 1.467 g/mL (that is, 132 g of chlorine).14.3 Attach a 38.10 mm piece of 1.59 mm TFE-fluorocarbon tubing and reducing fitting to the needle valve onthe chlorine cylinder, weigh, and record the sample cylinderweight to the nearest 0.1 g. Clamp the cylinder in a ring standwith the needle valve and fluoropolymer tubing pointed down.14.4 Cool a 15-mL centrifuge tube in crushed dry ice forseveral minutes.14.5 Fill a 1-mL plastic syringe with 1 mL of HPLC eluentand cool by placing it in crush
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