1、Designation: D 5176 08Standard Test Method forTotal Chemically Bound Nitrogen in Water by Pyrolysis andChemiluminescence Detection1This standard is issued under the fixed designation D 5176; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, 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 covers the determination of the totalnitrogen content of water in concentrations
3、from 0.5 to 1000mg/L. Higher nitrogen concentrations may be determined bymaking the proper dilutions.1.2 This test method does not determine molecular nitrogen(N2).1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This sta
4、ndard 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
5、ASTM Standards:2D 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on Water3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology D 1
6、129.3.2 Definition of Term Specific to This Standard:3.2.1 total chemically bound nitrogenall inorganic andorganic nitrogen in the sample, except molecular nitrogen (N2).4. Summary of Test Method4.1 The sample of water is introduced into a stream ofoxygen or inert/oxygen mix flowing through a quartz
7、 pyrolysistube. Oxidative pyrolysis converts chemically bound nitrogento nitric oxide (NO). The gas stream is dried and the NO iscontacted with ozone (O3) producing metastable nitrogendioxide (NO2*). As the NO2* decays, light is emitted anddetected by a photomultiplier tube. The resulting signal is
8、ameasure of the total chemically bound nitrogen in the sample.5. Significance and Use5.1 This test method is useful for the determination of totalchemically bound nitrogen in wastewaters and other waters.6. Apparatus36.1 Pyrolysis FurnaceAn electric tube furnace capable ofachieving a temperature of
9、1100C. The furnace may be singleor multizoned and may have common or separate and inde-pendent temperature controls.6.2 Pyrolysis TubeThe pyrolysis tube must be fabricatedfrom quartz and should be designed to ensure completepyrolysis of a wide variety of samples.6.3 Chemiluminescence DetectorThe det
10、ector shall havea photomultiplier tube capable of sensing the light emission ofthe decaying NO2*. The detector shall have digital display,onboard ozone generator and analog output for data system orstrip chart recorder.6.4 Recorder (optional)The recorder shall be able toaccept a 1 V full scale signa
11、l and to provide a chart speed of 1cm/min.6.5 Microlitre SyringeAny standard series of microlitresyringes with stainless steel needles is acceptable. See manu-facturers instructions for appropriate syringe sizes.6.6 Syringe Drive MechanismThe syringe drive shall becapable of driving the sample from
12、a microlitre syringe at acontrolled, reproducible rate.6.7 Sample BoatSamples with high concentrations ofsuspended matter or dissolved nonvolatile compounds maytend to plug the syringe needle upon injection into the pyrolysistube. In this case a sample boat of quartz or platinum, with orwithout quar
13、tz wool, should be used, in conjunction with the1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.06 on Methods forAnalysis forOrganic Substances in Water.Current edition approved May 1, 2008. Published June 2008. Originall
14、yapproved in 1991. Last previous edition approved in 2003 as D 5176 91 (2003).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 on
15、the ASTM website.3The apparatus described in 6.1-6.7 is manufactured by Antek Instruments, Inc.,Houston, TX and Dohrmann Division of Rosemount Analytical Inc., Santa Clara,CA, and was used in the validation study of this test method.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700,
16、West Conshohocken, PA 19428-2959, United States.appropriate pyrolysis tube. The pyrolysis tube shall allow theintroduction of the sample into the boat by microlitre syringewithout interrupting the gas flow system.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused. Un
17、less otherwise indicated, it is intended that all reagentsshall conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society.4Other grades may be used, provided it is first determined thatthe reagent is of sufficiently high purity to permit its usewithout les
18、sening the accuracy of the determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water that meetsthe purity specifications of Type I or Type II water, presentedin Specification D 1193.7.3 Inert Gas, Argon (minimum purity 99.99 %).7.4 Oxyg
19、en (minimum purity 99.6 %).7.5 Stock Solution, Pyridine (10 000 mg N/L)Prepare byaccurately weighing 5.647 g of pyridine into a 100 mLvolumetric flask and dilute to 100 mL with water.7.6 Pyridine Solutions, Standard (1000, 500, 100, 50, 10, 5,1, and 0.5 mg N/L)Dilute ten volumes of the stock solutio
20、n(see 6.5) with 90 volumes of water to prepare a 1000 mg N/Lstandard. Similarly, by serial dilution with water, prepare 500,100, 50, 10, 5, 1, and 0.5 mg N/L standards.8. Preparation of Apparatus8.1 Assemble apparatus according to manufacturers in-structions.9. Calibration and Standardization9.1 Use
21、 the water that was used to prepare the standards asa zero blank standard.9.2 A sample size of 5 to 10 L is sufficient to cover theconcentration range of this test method. The volume of thesample shall be accurately determined.9.3 Syringe InjectionFill the syringe to the 5 L mark andretract the plun
22、ger so that the liquid meniscus is at the 1 Lmark. Note the position of the plunger. Insert the syringeneedle through the inlet septum up to the syringe barrel andallow the furnace to burn all nitrogen bearing residue off thesyringe needle. Reset the detector and inject the sample at acontrolled rat
23、e of 1 to 2 L/s. A syringe drive mechanism (see6.6) is strongly recommended. When all sample has beeninjected, withdraw the syringe needle. Retract the plunger sothat the sample meniscus is again at the 1 L point and note theplunger position. The true amount injected is the differencebetween the two
24、 plunger positions.NOTE 1If water samples contain high concentrations of suspendedmatter or dissolved nonvolatile compounds, the syringe needle may tendto plug or the precision and bias of the test method may be degraded. Insuch a case, the sample boat system should be used (see 6.7).9.4 Boat Inject
25、ionFill the microlitre syringe to the markand inject the sample directly into the boat while holding theneedle in contact with the side of the boat or with the quartzwool.9.5 Determine each calibration standard and the zero blankthree times and record the net response from the average ofeach set of
26、standard responses.9.6 By injecting the same volumetric amount of sample foreach determination, the only variables will be total nitrogenconcentration and detector response (digital display). Constructa curve plotting milligrams of N per litre versus detectorresponse. Check the complete calibration
27、curve at least onceper week; check one or two standards daily.10. Procedure10.1 Flush the microlitre syringe several times with theunknown sample. Inject the sample at a controlled rate of 1 to2 g/s as described in 9.3 or inject the sample into the sampleboat (see 6.7) as described in 9.4.10.2 Set i
28、nstrument parameters as recommended by manu-facturers. Some changes may be needed to accommodatespecific kinds of samples.11. Calculation11.1 Determine the total chemically bound nitrogen contentof the water sample in milligrams N per litre by reading off thecalibration curve (see 9.6).12. Precision
29、 and Bias12.1 Collaborative TestUsing deionized water as thematrix, a stock solution was prepared containing ammoniumsulfate, potassium nitrate, and pyridine in such proportions thateach compound contributed about one-third of the total nitro-gen. Dilutions were made to provide samples of accurately
30、-known concentrations of about 0.5, 1, 10, 100, and 1000 mgN/L. This procedure was repeated, using nitrogen-containingwastewater as the matrix (the wastewater was expected to havea nitrogen content of approximately 20 mg/L, but the actualvalue was found to be about 150 mg/L). The ten samples plusuns
31、piked deionized (DI) water and unspiked wastewater (astrip blanks) were sent to 13 laboratories for analysis intriplicate according to this test method. The laboratories wererequired to make up their own standard solutions, and to usetheir own laboratory water to determine their instrument blank,tha
32、t they subtracted from their raw results before reportingthem.12.2 Analysis of ResultsOnly nine of the 13 laboratoriessubmitted results for this study. The data were processed asspecified in the 1986 edition of Practice D 2777. The whole ofone laboratorys results for the DI water matrix samples fail
33、edthe outlier test.Asingle result from another laboratory was alsorejected as an outlier. One laboratory reported only the averageof its three readings, without standard deviation, and anotherlaboratory did only duplicate runs; the results from these twolaboratories were used where possible. The ove
34、rall averagevalue for nitrogen in the blank wastewater was calculated by4Reagent 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 LaboratoryC
35、hemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.D5176082the collaborative test organizer, who then subtracted it from thereported values for the spiked wastewater samples.12.3 PrecisionSee Ta
36、ble 1.12.3.1 DI Water MatrixSingle-operator precision is poorat the low levels (1 mg N/L and lower) and adequate to goodat other levels. Overall precision is poor for the central valuesand very poor for the extremes.12.3.2 Wastewater MatrixBoth measures of precisionwere poor to very poor over the wh
37、ole range tested. This maybe attributed in part to the presence of some floccular sedimentin the matrix water that may not have been picked upconsistently by the syringes used in the test method.12.4 BiasSee Table 1.12.4.1 The negative bias values for the wastewater matrixsamples are larger than tho
38、se for the DI water matrix becauseof the subtraction of the N content of the matrix water from theraw data.13. Keywords13.1 chemiluminescence; nitrogen; pyrolysisASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this st
39、andard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be rev
40、iewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsi
41、ble technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West C
42、onshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 1 Precision a
43、nd BiasMatrix WaterAmount Added,mg N/LAmount Found,mg N/LNet Amount,Amg N/LPrecisionBias,mg N/LStSoDI 0.40 0.3 . 0.2 0.1 0.1B1.01 0.8 . 0.4 0.3 0.2B11.1 10.1 . 1.5 0.4 1.0B106 109 . 10 1.0 + 31105 1289 . 298 28 + 184BWaste 0.50 150 2 5 4 20.91 151 1 4 2 210.1 161 9 4 2 195.8 257 105 45 9 + 91008 1336 1184 330 43 + 176B. 152 0 18 3 .AAfter subtraction of wastewater matrixs N content.BBias significant at the 5 % level.D5176083
