1、Designation: E 200 97 (Reapproved 2001)e1Standard 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 ado
2、ption or, in the case of 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.This standard has been approved for use by agencies of the Department of Defense.e
3、1NOTEEditorial corrections were made in October 2001.1. Scope1.1 This practice 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
4、follows:SectionsReferenced Documents 2Terminology 3Significance and Use 4Apparatus 5Temperature effects 6Measurements 7Reagents 8Concentration of solutions 9Mixing of solutions 10Storage of solutions 11Preparation and standardization of solutions 12Precision and Bias 13Sodium hydroxide solution, 0.0
5、2 to 1.0 N 14 to 19Hydrochloric acid, 0.02 to 1.0 N 20 to 28Sulfuric acid, 0.02 to 1.0 N 29 to 33Hydrochloric acid, special 1 N 34 to 38Sulfuric acid, special 1N 39 to 43Silver nitrate solution, 0.1 N 44 to 48Ammonium thiocyanate solution, 0.1 N 49 to 53Iodine solution, 0.1 N 54 to 58Sodium thiosulf
6、ate solution, 0.1 N 59 to 63Potassium permanganate solution, 0.1 N 64 to 68Potassium dichromate solution, 0.1 N 69 to 73Methanolic sodium hydroxide solution, 0.5 N 74 to 79Ceric sulfate solution, 0.1 N 80 to 84Acetous perchloric acid, 0.1 N 85 to 89Disodium ethylenediaminetetraacetate solution, 0.05
7、 M 90 to 94Standard ion solutions 95Nonstandardized reagent solutions and indicator solutions 961.3 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 p
8、ractices and determine the applica-bility of regulatory limitations prior to use. Specific warningstatements are given throughout this practice.2. Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2E50 Practices for Apparatus, Reagents, and Safety Precau-tions for Chemical
9、 Analysis of Metals3E 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial Chemicals4E 203 Test Method for Water Using Karl Fischer Reagent4E 694 Specification for Volumetric Ware52.2 Other Document:Reagent Chemicals, American Chemical Society Specifi-cati
10、ons (ACS)63. Terminology3.1 Definition:3.1.1 standard volumetric solutiona solution of accuratelydetermined concentration used in the quantitative analysis ofchemicals and other products. The concentration of suchsolutions is usually expressed in terms of normality or molar-ity.4. Significance and U
11、se4.1 The accuracy of many analytical measurements is 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 practi
12、ce is under the jurisdiction of ASTM Committee E15 on Industrialand Specialty Chemicals and is the direct responsibility of Subcommittee E15.01 onGeneral Standards.Current edition approved July 10, 1997. Published June 1998. Originallypublished as E 200 62T. Last previous edition E 200 91.2Annual Bo
13、ok of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 03.05.4Annual Book of ASTM Standards, Vol 15.05.5Annual Book of ASTM Standards, Vol 14.02.6Available from American Chemical Society, 1155 16th St., N.W., Washington,DC 20036.1Copyright ASTM International, 100 Barr Harbor Drive, PO B
14、ox 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 Volumetric GlasswareThe use of ordinary volumetricglassware will meet the accuracy requirements of many testmethods.NOTE 1Fo
15、r dependable accuracy, volumetric glassware meeting therequirements for Class A items given in Specification E 694 should beused.While for normal work apparatus meeting these specifications can beused without calibration corrections, it is preferable that such calibrationcorrections be used in stand
16、ardizing 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 upon the glassmay result in changes in the apparent volume. It is recommended,therefore, that volumetric glassware, particu
17、larly 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-mL buretwith a 50-mL bulb at the top and a 50-mL stem below, may beused. For use with alkali solutions, burets equipped wit
18、hTFE-fluorocarbon stopcock plugs are preferable.6. Temperature Effects6.1 Volumetric solutions are often used at temperaturesdiffering from those at which the standardization was carriedout. Significant errors may be introduced when the solutionsare used at these other temperatures. Values for the c
19、hange 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 the work,normalities of standard solutions may be corrected to thetemperature at which they are used as follows:Nt25 Nt11
20、 t12 t2!F! (1)where:Nt1= normality of solution when standardized,Nt2= normality of solution when used,t1= temperature of solution during standardization, Ct2= temperature of solution during use, C, andF = factor to correct for thermal expansion of the solution(DN/C values from Table 1).6.2 From the
21、above equation it will be seen that thecorrection is to be added to the normality of the solution whenstandardized if the temperature of use is lower than thetemperature of standardization while the correction is to besubtracted if the temperature of use is higher than the tempera-ture of standardiz
22、ation.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 % or less. Where aspecific weight of substance is designated in a procedure, it isintended, unless otherwise specified in th
23、e 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 standards to be used in standardizingvolumetric solutions many laboratories customarily weigh to the nearest0.1 mg even though
24、 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 infers that a specific volume be measuredfrom a buret, the reading is to be estimated to one fifth of thesmallest volume sub
25、division 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 ResultsIt is customary to express thenormality and molarity of standard solutions to 1 part in 1000.8. ReagentsNOTE 3Additional inf
26、ormation on reagents is given in Practices E50.8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specific
27、ations are available.7Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity 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
28、 Type IIIreagent water conforming to Specification D 1193. Wherespecified, carbon dioxide-free water is to be prepared byheating 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 s
29、odalime-ascarite drying tube. For larger (10 to 20-L) volumes ofcarbon dioxide-free water, the absorbed carbon dioxide may 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 In
30、stitute of Standardsand Technology offers for sale certified standard samples ofarsenic trioxide, benzoic acid, potassium hydrogen phthalate,potassium dichromate, sodium oxalate, and tris(hydroxym-ethyl)aminomethane. Where specified, these samples, orsamples of commercially available primary standar
31、ds, are to beused in standardizing the volumetric solutions.7For suggestions on the testing of reagents not listed by the American ChemicalSociety, see “Analar Standards for Laboratory Chemicals,” BDH Ltd., Poole,Dorset, U.K., and the “United States Pharmacopeia.”TABLE 1 Temperature Correction Facto
32、rs (F)ApproximateNormalitySoluteDN/C for 20to 30C1.0 NaOH, HCl, H2SO40.000350.5 NaOH, HCl, H2SO40.000140.1 all aqueous 0.000020.05 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) HClO40.00011E 200 97 (2001)e129.
33、 Concentration of Solutions9.1 Standard SolutionsDirections are given for the prepa-ration of the most commonly used concentrations of thestandard volumetric solutions. Stronger or weaker solutions areprepared and standardized in the same general manner asdescribed, using proportionate amounts of th
34、e reagents. Simi-larly, if quantities larger than 1 L are to be prepared, propor-tionate amounts of the reagents should be used.9.2 Diluted Acids and Ammonium HydroxideConcentrations of diluted acids and ammonium hydroxide,except when standardized, shall be specified as a ratio statingthe number of
35、volumes of the concentrated reagent to bediluted with a given number of volumes of water, as in thefollowing example: HCl (5 + 95) means 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 areprepar
36、ed, special problems are encountered in being sure thatthey are well mixed before being standardized. While bladestirrers with glass 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
37、undesirable it may be possible to use a sealed polyolefin-coated stirrer. In those cases where only contact of the solutionwith metal 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 fo
38、r 1 or 2h.11. Storage of Solutions11.1 Glass containers are suitable for the storage of most ofthe standard solutions, although the use of polyolefin contain-ers is recommended for alkali solutions.11.2 When large quantities of solutions are prepared andstandardized, it is necessary to provide prote
39、ction againstchanges in normality due to absorption of gases or water vaporfrom the laboratory air. As volumes of solution are withdrawnfrom the container, the replacement air should be passedthrough a drying tube filled with equal parts of 8 to 20-meshsoda lime, oxalic acid, and 4 to 8-mesh anhydro
40、us calciumchloride, each product being separated from the other by aglass wool plug or use equivalent commercially availableabsorption tubes.12. Preparation and Standardization of Solutions12.1 Methods of standardization are given for each volu-metric solution even though the methods of preparation
41、forsome of these solutions specify that they be prepared on adeterminate basis. Since it is not possible to prepare 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 thesol
42、ution volumes cannot be made.13. Precision and Bias13.1 PrecisionPrecision for standardizing the volumetricsolutions in this practice was determined in accordance withPractice E 180 90 and the forms of the statements conformwith that suggested in Practice E 180 90.813.2 BiasNo information concerning
43、 the bias of thesestandardization methods is available because certified refer-ence solutions suitable for this practice are not available.STANDARD VOLUMETRIC SOLUTIONSSODIUM HYDROXIDE SOLUTION, 0.02 TO 1.0 N14. Preparation of 50 % NaOH Solution and of StandardSolutions14.1 Dissolve 162 g of sodium
44、hydroxide (NaOH) in 150mLof carbon dioxide-free water. Cool the solution to 25C andfilter through a hardened filter paper or other suitable medium.Alternatively, commercial 50 % NaOH solution may be used.14.2 To prepare a 0.1 N solution, dilute 5.45 mL of the clearsolution to 1 L with carbon dioxide
45、-free water, mix well, andstore in a tight polyolefin container.14.3 For other normalities of NaOH solution, use therequirements given in Table 2.15. Standardization15.1 Crush 10 to 20 g of primary standard potassiumhydrogen phthalate9(KHC8H4O4) to 100-mesh fineness, anddry in a glass container at 1
46、20C for 2 h. Stopper the containerand cool in a desiccator.15.2 To standardize a 0.1 N solution, weigh accurately 0.956 0.05 g of the dried KHC8H4O4, and transfer to a 500-mLconical flask. Add 100 mL of carbon dioxide-free water, stirgently to dissolve the sample, add 3 drops of a 1.0 % solutionof p
47、henolphthalein in alcohol, and titrate with NaOH solutionto a color that matches that of an end point color standard.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 M in boric ac
48、id (H3BO3)and 0.2 M in potassium chloride (KCl), (1.24 g H3BO3and1.49 KCl in 100 mL water) with 12 mL of 0.1 N NaOH8Data supporting the precision statements are available from ASTM Headquar-ters. Request RR: E-15-1039.9A primary standard grade of this chemical (and many others) is available fromthe
49、Office of Standard Reference Materials, National Institute of Standards andTechnology, Gaithersburg, MD 20899.TABLE 2 Sodium Hydroxide Dilution RequirementsDesiredNormalityGrams of NaOHRequired/1 L of SolutionVolume of 50 % NaOHSolution (25C)Required/1 L ofSolution, mL0.02 0.8 1.10.04 1.6 2.20.05 2.0 2.70.1 4.0 5.40.2 8.0 10.90.25 10.0 13.60.5 20.0 27.21.0 40.0 54.5E 200 97 (2001)e13solution, add 3 drops of a 1.0 % solution of phenolphthalein inalcohol, and dilute to 100 mL with carbon dioxide-free water.17. Calculation17.1 Calculate the normality of
