1、Designation: E 200 08Standard Practice forPreparation, Standardization, and Storage of Standard andReagent Solutions for Chemical Analysis1This standard is issued under the fixed designation E 200; the number immediately following the designation indicates the year oforiginal adoption or, in the cas
2、e 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This prac
3、tice covers procedures for the preparation,standardization, and storage of the standard volumetric solu-tions and reagent testing solutions commonly used in chemicalanalysis.1.2 The information in this practice is arranged as follows:SectionsReferenced Documents 2Terminology 3Significance and Use 4A
4、pparatus 5Temperature effects 6Measurements 7Reagents 8Concentration of solutions 9Mixing of solutions 10Storage of solutions 11Preparation and standardization of solutions 12Precision and Bias 13Sodium hydroxide solution, 0.02 to 1.0 meq/mL (N) 14to19Hydrochloric acid, 0.02 to 1.0 meq/mL (N) 20to28
5、Sulfuric acid, 0.02 to 1.0 meq/mL (N) 29to33Hydrochloric acid, special 1 meq/mL (N) 34to38Sulfuric acid, special 1meq/mL (N) 39to43Silver nitrate solution, 0.1 meq/mL (N) 44to48Ammonium thiocyanate solution, 0.1 meq/mL (N) 49to53Iodine solution, 0.1 meq/mL (N) 54to58Sodium thiosulfate solution, 0.1
6、meq/mL (N) 59to63Potassium permanganate solution, 0.1 meq/mL (N) 64to68Potassium dichromate solution, 0.1 meq/mL(N) 69to73Methanolic sodium hydroxide solution, 0.5 meq/mL (N) 74to79Ceric sulfate solution, 0.1 meq/mL (N) 80to84Acetous perchloric acid, 0.1 meq/mL (N) 85to89Disodium ethylenediaminetetr
7、aacetate solution, 0.05 mol/L(M)90 to 94Standard ion solutions 95Nonstandardized reagent solutions and indicator solutions 961.3 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of t
8、hesafety 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 warningstatements are given throughout this practice.2. Ref
9、erenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterE50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated MaterialsE 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial a
10、nd Spe-cialty ChemicalsE 203 Test Method forWater UsingVolumetric Karl FischerTitrationE 694 Specification for Laboratory Glass Volumetric Appa-ratus2.2 Other Document:Reagent Chemicals, American Chemical Society Specifi-cations (ACS)33. Terminology3.1 Definition:3.1.1 standard volumetric solutiona
11、solution of accuratelydetermined concentration used in the quantitative analysis ofchemicals and other products. The concentration of suchsolutions is usually expressed in terms of meq/mL (N) normal-ity or mol/L (M) molarity.4. Significance and Use4.1 The accuracy of many analytical measurements is
12、de-pendent upon the manner in which the standard solutions areprepared and stored, and the accuracy with which they arestandardized. Combining the methods recommended for thepreparation and handling of such solutions into one practice1This practice is under the jurisdiction of ASTM Committee E15 on
13、Industrialand Specialty Chemicals and is the direct responsibility of Subcommittee E15.01 onGeneral Standards.Current edition approved Dec. 15, 2008. Published January 2009. Originallyapproved in 1962 as as E 200 62T. Last previous edition approved in 2001 asE 200 97(2001)1.2For referenced ASTM stan
14、dards, 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.3Available from American Chemical Society, 1155 16th St., N.W., Washington,DC 20036.1*
15、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.eliminates the necessity for covering such details in all of themethods wherein the solutions are used.5. Apparatus5.1 Vo
16、lumetric GlasswareThe use of ordinary volumetricglassware will meet the accuracy requirements of many testmethods.NOTE 1For dependable accuracy, volumetric glassware meeting therequirements for Class A items given in Specification E 694 should beused.While for normal work apparatus meeting these spe
17、cifications can beused without calibration corrections, it is preferable that such calibrationcorrections be used in standardizing volumetric solutions. Such correc-tions may be of significance when the volumetric ware is frequently usedwith alkali solutions, for the corrosive effect of the alkali u
18、pon the glassmay result in changes in the apparent volume. It is recommended,therefore, that volumetric glassware, particularly burets and transferpipets, be recalibrated at 3-month intervals if it is frequently used tomeasure alkali solution volumes.5.2 BuretA 50-mL buret, or alternatively, a 100-m
19、L buretwith a 50-mL bulb at the top and a 50-mL stem below, may beused. For use with alkali solutions, burets equipped withTFE-fluorocarbon stopcock plugs are preferable.6. Temperature Effects6.1 Volumetric solutions are often used at temperaturesdiffering from those at which the standardization was
20、 carriedout. Significant errors may be introduced when the solutionsare used at these other temperatures. Values for the change ofnormality with temperature (D N/C) have been established forthe volumetric solutions described herein, and are listed inTable 1. When warranted by the desired accuracy of
21、 the work,normalities of standard solutions may be corrected to thetemperature at which they are used as follows:Nt25 Nt11 t12 t2!F! (1)where:Nt1= meq/mL (N) of solution when standardized,Nt2= meq/mL (N) of solution when used,t1= temperature of solution during standardization, Ct2= temperature of so
22、lution during use, C, andF = factor to correct for thermal expansion of the solution(DN/C values from Table 1).6.2 From the above equation it will be seen that thecorrection is to be added to the meq/mL (N) of the solutionwhen standardized if the temperature of use is lower than thetemperature of st
23、andardization while the correction is to besubtracted if the temperature of use is higher than the tempera-ture of standardization.7. Measurements7.1 WeighingsWhen it is directed that a chemical shouldbe “accurately weighed,” the weighing is to be performed in amanner so as to limit the error to 0.1
24、 % or less. Where aspecific weight of substance is designated in a procedure, it isintended, unless otherwise specified in the individual proce-dure, that a quantity within 65 % of the designated weight beused, and that this quantity be “accurately weighed” as justdefined.NOTE 2In weighing primary s
25、tandards to be used in standardizingvolumetric solutions many laboratories customarily weigh to the nearest0.1 mg even though such increased accuracy of weighing does notimprove the accuracy or precision of the standardization.7.2 Buret ReadingsWhen buret readings are specified, orwhen the procedure
26、 infers that a specific volume be measuredfrom a buret, the reading is to be estimated to one fifth of thesmallest volume subdivision marked on the buret. In reading a50-mL buret having subdivisions of 0.10 mL, therefore, thereading should be estimated to the nearest 0.02 mL.7.3 Expression of Result
27、sIt is recommended to expressthe concentration of the solutions as the normality in theequivalent SI units as meq/mL (N) and molarity as mol/L (M)8. ReagentsNOTE 3Additional information on reagents is given in Practices E50.8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unl
28、ess otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.4Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh pur
29、ity to permit its use without lessening the accuracy ofthe determination.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean Type II or Type IIIreagent water conforming to Specification D 1193. Wherespecified, carbon dioxide-free water is to be prepared byhe
30、ating distilled water to boiling in a conical flask, and boilingfor 20 min. The boiling water is cooled in the flask which isstoppered with a 1-hole rubber stopper fitted to a sodalime-ascarite drying tube. For larger (10 to 20-L) volumes ofcarbon dioxide-free water, the absorbed carbon dioxide may
31、beremoved by inserting a fritted-glass gas-dispersion tube to thebottom of the container and bubbling nitrogen through thewater for 1 or 2 h.8.3 Primary StandardsThe National Institute of Standardsand Technology offers for sale certified standard samples ofarsenic trioxide, benzoic acid, potassium h
32、ydrogen phthalate,potassium dichromate, sodium oxalate, and tris(hydroxym-ethyl)aminomethane. Where specified, these samples, orsamples of commercially available primary standards, are to beused in standardizing the volumetric solutions.4For suggestions on the testing of reagents not listed by the A
33、merican ChemicalSociety, see “Analar Standards for Laboratory Chemicals,” BDH Ltd., Poole,Dorset, U.K., and the “United States Pharmacopeia.”TABLE 1 Temperature Correction Factors (F)Approximatemeq/mL (N)SoluteDN/C for 20to 30C1.0 NaOH, HCl, H2SO40.000350.5 NaOH, HCl, H2SO40.000140.1 all aqueous 0.0
34、00020.05 all aqueous 0.000010.01 all aqueous 0.000000.5 (in methanol) NaOH 0.000450.1 (in 1 N H2SO4) Ce(SO4)20.0000350.1 (in glacial acetic acid) HClO40.00011E2000829. Concentration of Solutions9.1 Standard SolutionsDirections are given for the prepa-ration of the most commonly used concentrations o
35、f thestandard volumetric solutions. Stronger or weaker solutions areprepared and standardized in the same general manner asdescribed, using proportionate amounts of the reagents. Simi-larly, if quantities larger than 1 L are to be prepared, propor-tionate amounts of the reagents should be used.9.2 D
36、iluted Acids and Ammonium HydroxideConcentrations of diluted acids and ammonium hydroxide,except when standardized, shall be specified as a ratio statingthe number of volumes of the concentrated reagent to bediluted with a given number of volumes of water, as in thefollowing example: HCl (5 + 95) me
37、ans 5 volumes of concen-trated HCl (sp gr 1.19) diluted with 95 volumes of water.10. Mixing of Solutions10.1 When quantities of solution larger than 1 to 2 L areprepared, special problems are encountered in being sure thatthey are well mixed before being standardized. While bladestirrers with glass
38、or metal shafts are suitable for manysolutions, they are not suitable in every case. In those caseswhere contact of a glass or metal stirrer with the solution wouldbe undesirable it may be possible to use a sealed polyolefin-coated stirrer. In those cases where only contact of the solutionwith metal
39、 must be avoided, the solution can be mixed byinserting a fritted-glass gas-dispersion tube to the bottom of thecontainer and bubbling nitrogen through the solution for 1 or 2h.11. Storage of Solutions11.1 Glass containers are suitable for the storage of most ofthe standard solutions, although the u
40、se of polyolefin contain-ers is recommended for alkali solutions.11.2 When large quantities of solutions are prepared andstandardized, it is necessary to provide protection againstchanges in standardization concentration due to absorption ofgases or water vapor from the laboratory air. As volumes of
41、solution are withdrawn from the container, the replacement airshould be passed through a drying tube filled with equal partsof 8 to 20-mesh soda lime, oxalic acid, and 4 to 8-meshanhydrous calcium chloride, each product being separatedfrom the other by a glass wool plug or use equivalentcommercially
42、 available absorption tubes.12. Preparation and Standardization of Solutions12.1 Methods of standardization are given for each volu-metric solution even though the methods of preparation forsome of these solutions specify that they be prepared on adeterminate basis. Since it is not possible to prepa
43、re largevolumes of solutions on a determinate basis, a method ofstandardization is provided for those solutions that are preparedin such large volumes that accurate measurements of thesolution volumes cannot be made.13. Precision and Bias13.1 PrecisionPrecision for standardizing the volumetricsoluti
44、ons in this practice was determined in accordance withPractice E 180 90 and the forms of the statements conformwith that suggested in Practice E 180 90.513.2 BiasNo information concerning the bias of thesestandardization methods is available because certified refer-ence solutions suitable for this p
45、ractice are not available.STANDARD VOLUMETRIC SOLUTIONSSODIUM HYDROXIDE SOLUTION, 0.02 TO 1.0meq/mL N14. Preparation of 50 % NaOH Solution and of StandardSolutions14.1 Dissolve 162 g of sodium hydroxide (NaOH) in 150mLof carbon dioxide-free water. Cool the solution to 25C andfilter through a hardene
46、d filter paper or other suitable medium.Alternatively, commercial 50 % NaOH solution may be used.14.2 To prepare a 0.1 meq/mL (N) solution, dilute 5.45 mLof the clear solution to 1 L with carbon dioxide-free water, mixwell, and store in a tight polyolefin container.14.3 For other normalities of NaOH
47、 solution, use therequirements given in Table 2.15. Standardization15.1 Crush 10 to 20 g of primary standard potassiumhydrogen phthalate6(KHC8H4O4) to 100-mesh fineness, anddry in a glass container at 120C for 2 h. Stopper the containerand cool in a desiccator.15.2 To standardize a 0.1 meq/mL (N) so
48、lution, weighaccurately 0.95 6 0.05 g of the dried KHC8H4O4, and transferto a 500-mL conical flask. Add 100 mL of carbon dioxide-freewater, stir gently to dissolve the sample, add 3 drops of a 1.0 %solution of phenolphthalein in alcohol, and titrate with NaOHsolution to a color that matches that of
49、an end point colorstandard.15.3 The weights of dried KHC8H4O4suitable for othernormalities of NaOH solution are given in Table 3.16. pH 8.6 End Point Color Standard16.1 Mix 25 mL of a solution 0.2 mol/L (M) in boric acid(H3BO3) and 0.2 mol/L (M) in potassium chloride (KCl), (1.245Data supporting the precision statements are available from ASTM Headquar-ters. Request RR: E-15-1039.6A primary standard grade of this chemical (and many others) is available fromthe Office of Standard Reference Materials, National Institute of Standards andTechnology, Gaith
