1、Designation: D2194 02 (Reapproved 2012)Standard Test Method forConcentration of Formaldehyde Solutions1This standard is issued under the fixed designation D2194; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers the determination of
3、the form-aldehyde content of commercially available formaldehydesolutions ranging in concentration from 36 to 55 weight %.1.2 For purposes of determining conformance of an ob-served value or a calculated value using this test method torelevant specifications, test result(s) shall be rounded off “tot
4、he nearest unit” in the last right-hand digit used in expressingthe specification limit, in accordance with the rounding-offmethod of Practice E29.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 For hazard information an
5、d guidance, see the suppliersMaterial Safety Data Sheet.1.5 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-bilit
6、y of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications3. Summary of Test Method3.1 The specimen is reacted with an excess of sodium sul
7、fitesolution and the resulting sodium hydroxide is titrated withsulfuric acid using thymolphthalein indicator.3.2 The sample should be essentially neutral; 0.1 % acidity(as formic acid) is equivalent to 0.065 % formaldehyde.4. Significance and Use4.1 This test method provides a measurement of formal
8、de-hyde content (assay) of formaldehyde solutions. The results ofthese measurements can be used for specification acceptance.5. Apparatus5.1 Buret, calibrated, 100-mL, with a 50 or 75-mL reservoiron top of a lower portion calibrated in 0.1-mL divisions. ATFE-fluorocarbon resin stopcock is suitable f
9、or this purpose.5.2 Erlenmeyer Flask, 500-mL capacity.5.3 Vials, specimen, short, style, 1 to 112-dram (4 to 6-mL)capacity.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specificatio
10、ns of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 Puri
11、ty of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Type IV of Specification D1193.6.3 Sodium Sulfite Solution (125 g/L)Dissolve 125 g ofanhydrous sodium sulfite (Na2SO3) in water and dilute to 1 L.NOTE 1Sodium sulfite gradually oxidizes t
12、o sodium sulfate onexposure to air and therefore should be kept in a tightly closed container.For best results freshly prepared reagent should be used.6.4 Sulfuric Acid (0.5 N)Prepare and standardize 0.5 Nsulfuric acid (H2SO4) against 0.5 N sodium hydroxide (NaOH)1This test method is under the juris
13、diction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.35 on Solvents, Plasticizers, and Chemical Intermediates.Current edition approved July 1, 2012. Published September 2012. Originallyapproved in 1963. Last previ
14、ous edition approved in 2007 as D2194 02 (2007).DOI: 10.1520/D2194-02R12.2For 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 A
15、STM website.3Reagent 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 United Stat
16、es Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.*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 States1solution which has been s
17、tandardized against potassium acidphthalate to a thymolphthalein end point.6.5 Thymolphthalein Indicator (0.1 % Alcohol Solution)Dissolve 1.0 g of thymolphthalein in 100 mL of methanol,ethanol, or isopropanol and dilute to 1 L with additionalalcohol.7. Procedure7.1 Add 100 mL of Na2SO3solution to a
18、sufficient numberof 500-mL Erlenmeyer flasks to make all blank and specimendeterminations in duplicate.7.2 Weigh a 2-g specimen to the nearest 0.1 mg in theweighing vials and transfer the vials to the Erlenmeyer flasks,being careful to avoid getting any of the sample on the sides ofthe flasks.7.3 Ad
19、d 3 to 5 drops of the thymolphthalein indicatorsolution to each of the flasks containing specimens as well asthe blanks and titrate to a colorless end point.8. Calculation8.1 Calculate the weight percent of formaldehyde, W,asfollows:W 5 V 2 B! 3 N 3 F#/S 3100 (1)where:V =H2SO4required for titration
20、of the specimen, mL,B =H2SO4required for titration of the blank, average, mL,N = normality of the H2SO4,F = 0.03003 (the milliequivalent weight of formaldehyde),andS = sample used, g.9. Report9.1 Report the percent formaldehyde to the nearest 0.01 %.Duplicate runs that agree within 0.12 % are accept
21、able foraveraging (95 % confidence level).10. Precision and Bias10.1 The following criteria should be used for judging theacceptability of results at the 95 % confidence level.10.1.1 RepeatabilityThe difference between two results,each the mean of duplicate determinations, obtained by thesame analys
22、t on different days is normally about 0.05 %absolute. Two such results should be considered suspect if theydiffer by more than 0.12 % absolute.10.1.2 ReproducibilityThe average difference betweentwo results (each the mean of duplicate determinations) ob-tained by analysts in different laboratories i
23、s normally about0.08 % absolute. Two such results should be consideredsuspect if they differ by more than 0.23 % absolute.NOTE 2The above precision estimates are based on two interlabora-tory studies involving five and nine laboratories, respectively, using twodifferent samples in each case with a s
24、ingle analyst performing duplicateresults on each of two days. The formaldehyde levels studied were asfollows: 36.85 %, 36.98 %, 37.15 %, and 37.23 %.10.2 BiasBias has not been determined for this testmethod because primary standards do not exist.11. Keywords11.1 concentration; formaldehydeSUMMARY O
25、F CHANGESCommittee D01.35 has identified the location of selected changes to this standard since the last issue(D2194 - 99) that may impact the use of this standard.(1) Added reference to Practice E29 in Scope section. (2) Added Practice E29 to list of Referenced Documents.ASTM International takes n
26、o position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. 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 respon
27、sibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed 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
28、to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible 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 ad
29、dress shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D2194 02 (2012)2
