1、Designation: E200 16Standard Practice forPreparation, Standardization, and Storage of Standard andReagent Solutions for Chemical Analysis1This standard is issued under the fixed designation E200; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、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 U.S. Department of Defense.1. Scope*1.1 This p
3、ractice 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
4、 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, 0.02 to 1.0 meq/mL (N) 14 to 19Hydrochloric acid, 0.02 to 1.0 meq/mL (N) 2
5、0 to 28Sulfuric acid, 0.02 to 1.0 meq/mL (N) 29 to 33Hydrochloric acid, special 1 meq/mL (N) 34 to 38Sulfuric acid, special 1 meq/mL (N) 39 to 43Silver nitrate solution, 0.1 meq/mL (N) 44 to 48Ammonium thiocyanate solution, 0.1 meq/mL (N) 49 to 53Iodine solution, 0.1 meq/mL (N) 54 to 58Sodium thiosu
6、lfate solution, 0.1 meq/mL (N) 59 to 63Potassium permanganate solution, 0.1 meq/mL (N) 64 to 68Potassium dichromate solution, 0.1 meq/mL(N) 69 to 73Methanolic sodium hydroxide solution, 0.5 meq/mL (N) 74 to 79Ceric sulfate solution, 0.1 meq/mL (N) 80 to 84Acetous perchloric acid, 0.1 meq/mL (N) 85 t
7、o 89Disodium ethylenediaminetetraacetate 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
8、 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. Specific warningstatements are given
9、 throughout this practice.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterE50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated MaterialsE180 Practice for Determining the Precision of ASTMMethods for Analys
10、is and Testing of Industrial and Spe-cialty Chemicals (Withdrawn 2009)3E203 Test Method for Water Using Volumetric Karl FischerTitrationE694 Specification for Laboratory Glass Volumetric Appa-ratus2.2 Other Document:4Reagent Chemicals, American Chemical Society Specifica-tions (ACS)3. Terminology3.1
11、 Definitions: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 meq/mL (N) normal-ity or mol/L (M) molarity.4. Significance and Use4.1
12、 The accuracy of many analytical measurements is de-pendent upon the manner in which the standard solutions are1This practice is under the jurisdiction of ASTM Committee E15 on Industrialand Specialty Chemicals and is the direct responsibility of Subcommittee E15.01 onGeneral Standards.Current editi
13、on approved April 1, 2016. Published May 2016. Originallyapproved in 1962 as E200 62T. Last previous edition approved in 2008 asE200 08. DOI: 10.1520/E0200-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of
14、ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American Chemical Society (ACS), 1155 Sixteenth St., NW,Washington, DC 20036, http:/www.acs.org.*A Sum
15、mary 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 States1prepared and stored, and the accuracy with which they arestandardized. Combining the methods recommended for thepreparation and
16、 handling of such solutions into one practiceeliminates 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 1For dependable
17、 accuracy, volumetric glassware meeting therequirements for Class A items given in Specification E694 should beused.While for normal work apparatus meeting these specifications can beused without calibration corrections, it is preferable that such calibrationcorrections be used in standardizing volu
18、metric 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, particularly burets
19、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 withTFE-fluoroca
20、rbon 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 change ofnorma
21、lity with temperature (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 Nt11t12 t2!F! (1)wh
22、ere: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 solution during use, C, andF = factor to correct for thermal expansion of the solution(N/C values from Table 1).6.2 From the above equation i
23、t 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 standardization while the correction is to besubtracted if the temperature of use is higher than the tempera-ture of standardization.7. Measur
24、ements7.1 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 the individualpro
25、cedure, that a quantity within 65 % of the designatedweight be used, and that this quantity be “accurately weighed”as just defined.NOTE 2In weighing primary standards to be used in standardizingvolumetric solutions many laboratories customarily weigh to the nearest0.1 mg even though such increased a
26、ccuracy 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 subdivision marked o
27、n 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 recommended to express theconcentration of the solutions as the normality in the equivalentSI units as meq/mL (N) and molarity as mol/L
28、 (M).8. ReagentsNOTE 3Additional information 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
29、 Chemical Society wheresuch specifications are available.5Other 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 sh
30、all be understood to mean Type II or Type IIIreagent water conforming to Specification D1193. 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
31、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 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
32、.3 Primary StandardsThe National Institute of Standardsand Technology offers for sale certified standard samples ofarsenic trioxide, benzoic acid, potassium hydrogen phthalate,potassium dichromate, sodium oxalate, and tris(hydroxymeth-yl)aminomethane. Where specified, these samples, or samples5For s
33、uggestions on the testing of reagents not listed by the American ChemicalSociety, see “United States Pharmacopeia.”TABLE 1 Temperature Correction Factors (F)Approximatemeq/mL (N)SoluteN/C for 20to 30C1.0 NaOH, HCl, H2SO40.000350.5 NaOH, HCl, H2SO40.000140.1 all aqueous 0.000020.05 all aqueous 0.0000
34、10.01 all aqueous 0.000000.5 (in methanol) NaOH 0.000450.1 (in 1 N H2SO4) Ce(SO4)20.0000350.1 (in glacial acetic acid) HClO40.00011E200 162of commercially available primary standards, are to be used instandardizing the volumetric solutions.9. Concentration of Solutions9.1 Standard SolutionsDirection
35、s 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 the reagents.Similarly, if quantities larger than 1 L are to
36、 be prepared,proportionate 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 volumes of the concentrated reagent to bediluted with a given
37、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 areprepared, special problems are encountered in being sure thatthey ar
38、e 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 undesirable it may be possible to use a sealed polyolefin-coat
39、ed 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 for 1 or2h.11. Storage of Solutions11.1 Glass containers are sui
40、table 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 protection againstchanges in standardization concentration due to ab
41、sorption ofgases or water vapor from the laboratory air. As volumes ofsolution 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 sepa
42、ratedfrom the other by a glass wool plug or use equivalentcommercially 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 the
43、y 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 thesolution volumes cannot be made.13. Precision
44、and Bias613.1 PrecisionPrecision for standardizing the volumetricsolutions in this practice was determined in accordance withPractice E180 90 and the forms of the statements conformwith that suggested in Practice E180 90.13.2 BiasNo information concerning the bias of thesestandardization methods is
45、available because certified refer-ence solutions suitable for this practice are not available.STANDARD VOLUMETRIC SOLUTIONSSODIUM HYDROXIDE SOLUTION,0.02 TO 1.0 meq/mL N14. Preparation of 50 % NaOH Solution and of StandardSolutions14.1 Dissolve 162 g of sodium hydroxide (NaOH) in150 mLof carbon diox
46、ide-free water. Cool the solution to 25Cand filter through a hardened filter paper or other suitablemedium. Alternatively, commercial 50 % NaOH solution maybe 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
47、 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 phthalate7(KHC8H4O4) to 100-mesh fineness, anddry in a glass container at 120C for 2 h. Stopper the contai
48、nerand cool in a desiccator.15.2 To standardize a 0.1 meq/mL (N) solution, 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 alco
49、hol, and titrate with NaOHsolution to a color that matches that of 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),(1.24 g H3BO3and 1.49 KCl in 100 mL water) with 12 mL of0.1 N NaOH solution, add 3 drops of a 1.0 % solution ofphenolphthalein in alcohol, and dilute to 100 mL with carbondioxide-free water.17. Calculation17.1 Ca
