1、Designation: D1608 98 (Reapproved 2009)D1608 16Standard Test Method forOxides of Nitrogen in Gaseous Combustion Products(Phenol-Disulfonic Acid Procedures)1This standard is issued under the fixed designation D1608; the number immediately following the designation indicates the year oforiginal adopti
2、on 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 the phenol-disulfonic acid colorimetric procedu
3、re (1)2 for the determination of total oxides ofnitrogen nitrous oxide (N2O) excepted in gaseous effluents from combustion and other nitrogen oxidation processes.1.2 It is applicable to a concentration range of oxides of nitrogen as nitrogen dioxide (NO2) of 5 ppm to several thousand partsper millio
4、n by volume (four to several thousand milligrams per dry standard cubic metre).1.3 Since the grab sampling technique used takes a relatively small sample over a very short period of time, the result obtainedwill be an instantaneous measure of the nitrogen oxides and, therefore, will be representativ
5、e of the emissions only if the gas streamis well mixed and the concentration constant with time. Multiple samples are recommended.1.4 The values stated in SI units are to be regarded as standard. The SI equivalents are in parentheses and may beapproximate.values given in parentheses are mathematical
6、 conversions to inch-pound units that are provided for information onlyand are not considered standard.1.5 WarningMercury has been designated by many regulatory agencies as a hazardous material that can cause seriousmedical issues. Mercury, or its vapor, has been demonstrated to be hazardous to heal
7、th and corrosive to materials. Caution shouldbe taken when handling mercury and mercury containing products. See the applicable product Safety Data Sheet (SDS) foradditional information. Users should be aware that selling mercury and/or mercury containing products into your state or countrymay be pr
8、ohibited by law.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.
9、(For more specific safety precautionary information see 8.5 and Section 3.)2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1356 Terminology Relating to Sampling and Analysis of AtmospheresD1357 Practice for Planning the Sampling of the Ambient AtmosphereD1605 Practic
10、es for Sampling Atmospheres for Analysis of Gases and Vapors (Withdrawn 1992)3E1 Specification for ASTM Liquid-in-Glass ThermometersE2251 Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids3. Terminology3.1 DefinitionsFor definitions of terms used in this test metho
11、d, refer to Terminology D1356.4. Summary of Test Method4.1 The gas sample is admitted into an evacuated flask containing an oxidizing absorbing solution consisting of hydrogenperoxide in dilute sulfuric acid. The oxides of nitrogen are converted to nitric acid by gas phase oxidation due to oxygen in
12、 the1 This test method is under the jurisdiction of ASTM Committee D22 on Air Quality and is the direct responsibility of Subcommittee D22.03 on Ambient Atmospheresand Source Emissions.Current edition approved March 1, 2009March 1, 2016. Published March 2009March 2016. Originally approved in 1958. L
13、ast previous edition approved in 20032009 asD1608 98 (2003).(2009). DOI: 10.1520/D1608-98R09.10.1520/D1608-16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the sta
14、ndards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous versi
15、on. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM Internationa
16、l, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1sample and by the absorbent solution. The resulting nitrate ion is reacted with phenol disulfonic acid to produce a yellowcompound (the tri-ammonium salt of 6-nitro-1-phenol-2,4-disulfonic acid), which is measured
17、 colorimetrically. Calibration curves,prepared from samples of known nitrate content, are used to determine the amount of nitrate in the sample with results expressedas nitrogen dioxide.5. Significance and Use5.1 This test method provides a means to measure the total nitrogen oxides (NOx) content of
18、 gaseous emissions for purposessuch as determining compliance with regulations, studying the effect of various abatement procedures on NOx emissions, andchecking the validity of instrumental measurements.6. Interferences (1, 2)46.1 Inorganic nitrates, nitrites, or organic nitrogen compounds that are
19、 easily oxidized to nitrates interfere with the test methodand give erroneously high results. The presence of certain reducing agents, for example, sulfur dioxide (SO2), may interfere byconsuming part of the hydrogen peroxide in the absorbing solution to leave an inadequate amount for reaction with
20、the oxides ofnitrogen. Halides lower the results, but interference from halide ion (and lead) are negligible in the concentration usuallyencountered in combustion sources.6.2 The role of some of the constituents of combustion effluents as possible interfering substances has not been thoroughlyinvest
21、igated.7. Apparatus7.1 The assembled sampling apparatus is shown in Fig. 1.7.2 Barometer, capable of measuring atmospheric pressure to 6250 Pa 62 mm Hg.7.3 Bottles, 120-mL or 4-oz, glass or polyethylene, with leak-free noncontaminating caps.7.4 Evaporating Dishes, new condition, unetched borosilicat
22、e glass or porcelain, about 200-mL capacity. Do not use platinumware (3).7.5 Mercury Manometer, open-end U-tube, 1 mm or 36 in. with 1-mm or 0.1-in. divisions.NOTE 1An unbreakable, roll-up type is convenient for this application.7.6 Microburet, 10-mL capacity, with 0.01-mL divisions.7.7 pH Paper, or
23、 litmus paper, covering the range from 7 to 14 pH.7.8 Sample Collection Flask, CalibratedTwo-litre round-bottom glass flask with a short neck 24/40 standard-taper joint,protected against implosion or breakage with tape or foamed plastic, with known volume.7.9 Sampling Probe, borosilicate glass, appr
24、oximately 6-mm inside diameter, fitted with a 12/5 spherical joint for attachmentto the three-way stopcock on the sample collection flask, provided with a filter on the inlet end for removal of particulate matter,long enough to extend from approximately one-third to halfway into the stack or duct (o
25、r at least 1 m beyond inside wall of stacksgreater than 2 m in diameter), and heated or insulated, or both, sufficiently well to prevent condensation of moisture while purgingand sampling.4 The boldface numbers in parentheses refer to a list of references at the end of this standard.FIG. 1 Diagram o
26、f Typical Sampling Apparatus used for Determination of Oxides of Nitrogen by Test Method D1608D1608 1627.10 Spectrophotometer, or filter photometer, capable of measuring absorbance at 405 nm.NOTE 2A wavelength of 400 nm was actually used in the Project Threshold tests, but recent work (4, 5, 3) has
27、shown that the absorbance peakmaximum is actually at 405 nm, which is therefore a better choice. This change should tend to improve the precision and bias of the test method.7.11 Squeeze-bulb,Squeeze-Bulb, rubber, valved for one-way flow to purge sampling probe.7.12 Stirring Rod, polyethylene, to av
28、oid scratching the evaporating dishes.7.13 Stopcock, Three-way, T-bore,Three-Way, T-Tore, with a 24/40 joint for attachment to the sample collection flask, and a 12/5spherical joint for attachment to the sampling probe.7.14 Stopcock Grease, high vacuum, high temperature, inert.7.15 Thermometer, dial
29、-type or glass, with 1C 2F divisions and an approximate range from 5 to 50C 25 to 125F.ASTMThermometer 33C, meeting the requirements of Specification E1 will meet the requirements of most applications in this method.A comparable precision low-hazard liquid thermometer, ASTM Thermometer S33C, meeting
30、 the requirements of SpecificationE2251, may also be used.7.16 Vacuum Pump, portable, capable of evacuating the sample collection flask to a pressure of about 2.5 kPa 25 mm Hg orless.7.17 Volumetric Flasks, 50, 100, 1000-mL capacity.7.18 Volumetric Pipets, 1, 2, 3, 4, and 5-mL capacity.7.19 Water Ba
31、th or Steam Bath, operating at approximately 100C 212F (an electric hot plate is not suitable because it tendsto cause spattering and possible loss of sample).8. Reagents8.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreage
32、nts shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, wheresuch specifications are available.5 Other reagents may be used provided it can be demonstrated that they are of sufficiently highpurity to permit their use without decreasing the ac
33、curacy of the determination.8.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water conforming toType III or better of Specification D1193. Additionally, this test method requires water that is nitrate-free as demonstrated by alow-blank absorbance
34、 reading (less than 0.002 nm) in Section 5.8.3 Absorbing SolutionDilute 3.0 mL of hydrogen peroxide (H2O2, 3 %) to 100 mL with sulfuric acid solution (H2SO4,3+997). A fresh solution shall be prepared weekly. Do not expose to excessive heat or direct sunlight for prolonged time.8.4 Ammonium Hydroxide
35、 (sp gr 0.90)Concentrated ammonium hydroxide (NH4OH). A fresh solution shall be used.8.5 Fuming Sulfuric Acid (H2SO4 XSO3), 15 to 18 weight % free sulfur trioxide. Caution(WarningHandle with careHandle with care. )8.6 Hydrogen Peroxide (3 %)Dilute 10 mL of concentrated H2O2 (30 %) to 100 mL. A fresh
36、 solution shall be prepared eachtime new absorbing solution is prepared.NOTE 3If the strength of the H2O2 (30 %) is in doubt, test as follows: Weigh accurately about 5 mL of the H2O2 solution and dilute to exactly 500mL. To 20 mL of the dilute solution add 20 mL of H2SO4 (1+9) and titrate with 0.1 N
37、 potassium permanganate (KMnO4) solution to a permanent pinkcolor. One millilitre of 0.1 N KMnO4 solution = 0.001701 g of H2O2.8.7 Phenol (C6H5 OH), pure white solid.8.8 Phenol Disulfonic Acid SolutionDissolve 25 g of phenol in 150 mL of concentrated H2SO4 (sp gr 1.84) by heating on asteam bath. Coo
38、l, add 75 mL of fuming H2SO4 (15 to 18 % SO3) and heat on the steam bath at 100C 212F for 2 h. Cool andstore in a dark glass-stoppered bottle. The solution should be colorless; it deteriorates on long standing. Discard if a yellow colordevelops.8.9 Potassium Nitrate (KNO3)Dry in an oven at 105 to 11
39、0C for 2 h just before preparation of the standard solution.8.10 Potassium Nitrate, Stock Standard Solution (1 mL = 1 mg NO2)Dissolve exactly 2.1980 g of dried KNO3 in water anddilute to 1 L in a volumetric flask.8.11 Potassium Nitrate, Working Standard Solution (1 mL = 100 g NO2)Dilute 10 mLof the
40、stock standard potassium nitratesolution (1 mL = 1 mg NO2) to 100 mL with water in a volumetric flask.5 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see A
41、nalar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D1608 1638.12 Sodium Hydroxide Solution (;1 N)Slowly add 40 g of sodium hydroxide (NaOH) pellets to 800 to 900
42、mL of water ina 2-L beaker with stirring until all pellets are dissolved. Dilute to 1 L with water and mix well. Store in an airtight polyethyleneor polypropylene bottle.8.13 Sulfuric Acid (sp gr 1.84)Concentrated H2SO4, minimum assay 95 %.8.14 Sulfuric Acid (3+997)Carefully add 3 mL of concentrated
43、 H2SO4 (sp gr 1.84) to water and dilute to 1 L.9. Safety Precautions9.1 WarningReagents used in this method are potentially hazardous and many are extremely reactive. Concentrated acids andbases are used throughout the laboratory procedure. Use care when adding them to other solutions to avoid overh
44、eating and skincontact. Refer to material safety datasheets for reagents.9.2 WarningAvoid exposure to chemicals and solvents used in this method. Sample and standard preparations should be donein an efficient operating hood.9.3 WarningWear safety glasses at all times and other laboratory protective
45、equipment as appropriate.9.4 CoverWarningCover the glass sample collection flask, which is evacuated during the sampling procedure, with tape orfoamed plastic to avoid injury in case of implosion or breakage. the glass sample collection flask, which is evacuated during thesampling procedure, with ta
46、pe or foamed plastic to avoid injury in case of implosion or breakage.9.5 TheWarningThe fuming sulfuric acid used in preparing the phenol disulfonic acid reagent is highly corrosive and fumesin moist air. Wear protective gloves, apron, and face shield, and carry out the reagent preparation in a hood
47、. fuming sulfuric acidused in preparing the phenol disulfonic acid reagent is highly corrosive and fumes in moist air. Wear protective gloves, apron, andface shield, and carry out the reagent preparation in a hood.9.3 Concentrated acids and bases are used throughout the laboratory procedure. Use car
48、e when adding them to other solutionsto avoid overheating and skin contact.10. Sampling10.1 Pipet 25.0 mL of absorbing solution into a calibrated sampling flask and attach the three-way stopcock to the flask (seeNote 4) with the T-bore in the purge position. Insert the sampling probe tip from approx
49、imately one-third to halfway into the stackor duct, or at least 1 m into stacks greater than 2 m in diameter, in such a way as to prevent leakage of air into the stack aroundthe probe. Assemble as shown in Fig. 1, making sure that all ground-glass joints have been properly greased, and that all jointsand fittings are tight and leak-free. Turn the flask stopcock to the evacuate position and evacuate the flask to the incipient boilingof the solution. If the incipient boiling of the solution cannot be seen, this will be indica
copyright@ 2008-2019 麦多课文库（www.mydoc123.com）网站版权所有
备案/许可证编号：苏ICP备17064731号-1