GB/T 3051-2025 PDF English
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GB/T 3051: Historical versions
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| GB/T 3051-2025 | 230 | Add to Cart | Auto, 9 seconds. | General methods for the determination of chloride content in inorganic chemical products - Mercurimetric method and ion chromatography method | Valid |
| GB/T 3051-2000 | 100 | Add to Cart | Auto, 9 seconds. | Inorganic chemical products for industrial use. General method for determination of chloridecontent. Mercurimetric method | |
| GB/T 3051-1982 | RFQ | ASK | 3 days | Inorganic chemical products for industrial use--General method for determination of chloride content--Mercurimetric method | Obsolete |
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GB/T 3051-2025: General methods for the determination of chloride content in inorganic chemical products - Mercurimetric method and ion chromatography method
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GB NATIONAL STANDARD OF THE PEOPLE'S REPUBLIC OF CHINA ICS 71.060.01 CCS G 10 Replacing GB/T 3051-2000 General methods for the determination of chloride content in inorganic chemical products - Mercurimetric method and ion chromatography method Issued on: AUGUST 1, 2025 Implemented on: FEBRUARY 1, 2026 Issued by. State Administration for Market Regulation; Standardization Administration of PRC.
Table of Contents
Foreword... 3 1 Scope... 5 2 Normative references... 5 3 Terms and definitions... 6 4 General provisions... 6 5 Mercurimetric method... 6 6 Ion chromatography... 8 7 Precision... 11 8 Recovery... 11 Appendix A (Informative) Ions that do not interfere with the determination, ions that interfere with the determination, and co-existing interfering substances and their limits ... 12 Appendix B (Informative) Chloride (as Cl) in the test solution and the corresponding mercuric nitrate standard titration solution... 14 Appendix C (Informative) Interfering ion elimination... 15 Appendix D (Informative) Treatment methods for mercury-containing wastewater.. 18 General methods for the determination of chloride content in inorganic chemical products - Mercurimetric method and ion chromatography method WARNING. Some of the reagents used in this document are hazardous and shall be handled with caution! Personnel using this document shall have practical experience in formal laboratory work. This document does not address all possible safety issues. Users are responsible for taking appropriate safety and health measures and ensuring compliance with relevant national laws and regulations.1 Scope
This document provides the general provisions, reagents or materials, instruments and equipment for the mercurimetric method and ion chromatography method for the determination of chloride content in inorganic chemical products. It also describes the principles, experimental procedures, experimental data processing, and precision and recovery of the mercurimetric method and ion chromatography method for the determination of chloride content in inorganic chemical products. This document applies to the determination of chloride content in inorganic chemical products by the mercurimetric method and ion chromatography. For the mercurimetric method, the specimens containing the chloride (as Cl) of 0.01 mg~80 mg shall be determined by titrating in an ethanol solution, when the concentration of the mercuric nitrate standard solution used is less than 0.02 mol/L. The ion chromatography method has a determination range (mass fraction) of 0.0001%~1%.2 Normative references
The provisions of the following documents constitute the essential clauses of this document through normative references in this text. Among them, for any dated reference, only the version corresponding to that date applies to this document; for any undated reference, the latest version (including all amendments) applies to this document. GB/T 6379.2 Accuracy (trueness and precision) of measurement methods and results - Part 2.Basic method for the determination of repeatability and reproducibility of a standard measurement method GB/T 6682-2008 Water for analytical laboratory use - Specification and test methods GB/T 31197 Inorganic chemicals for industrial use - Determination of impurity anions - Ion chromatography method HG/T 3696.1 Inorganic chemicals for industrial use - Preparations of standard and reagent solutions for chemical analysis - Part 1.Preparations of standard volumetric solutions HG/T 3696.2 Inorganic chemicals for industrial use - Preparations of standard and reagent solutions for chemical analysis - Part 2.Preparations of standard solutions for impurity HG/T 3696.3 Inorganic chemicals for industrial use - Preparations of standard and reagent solutions for chemical analysis - Part 3.Preparations of reagent solutions3 Terms and definitions
The terms and definitions defined in GB/T 31197 apply to this document.4 General provisions
Unless otherwise specified, the reagents and water used in this document refer to analytically pure reagents and the Grade 3 water specified in Table 1 of GB/T 6682- 2008.Standard titration solutions, impurity standard solutions, preparations, and products used in the tests, unless otherwise specified, are prepared in accordance with the requirements of HG/T 3696.1, HG/T 3696.2, and HG/T 3696.3.5 Mercurimetric method
5.1 Principle In slightly acidic water or ethanol solution, a strongly ionized mercuric nitrate standard titration solution is used to convert chloride ions into weakly ionized mercuric chloride, and diphenylcarbazone indicator solution is used to react with excess Hg2+ to form a purple-red complex to determine the endpoint. 5.2 Reagents or materials 5.2.1 Nitric acid solution. 1+19. 5.2.2 Sodium hydroxide solution. 40 g/L. 5.2.3 Mercuric nitrate standard titration solution I. c[1/2Hg(NO3)2]≈0.1 mol/L. 5.2.4 Mercuric nitrate standard titration solution II. c[1/2Hg(NO3)2]≈0.01 mol/L, c[1/2Hg(NO3)2]≈0.005 mol/L, c[1/2Hg(NO3)2]≈0.001 mol/L. Accurately dilute the mercuric nitrate standard titration solution I by the required multiple. During dilution, add an appropriate amount of nitric acid solution (1+1) to prevent hydrolysis of the mercuric nitrate. 5.2.5 Bromophenol blue indicator solution (0.4 g/L). 5.2.6 Diphenylcarbazone indicator solution (0.25 g/L). 5.3 Instruments and equipment Microburette. The graduation value is 0.01 mL or 0.02 mL. 5.4 Test steps 5.4.1 Preparation of test solution Weigh an appropriate amount of specimen to the nearest 0.0002 g. Treat using an appropriate method, or transfer an appropriate amount of test solution after chemical treatment (so that interfering ions do not exceed the specified limits, see Appendix A; chlorine content is 0.01 mg~80 mg). Place the solution in a conical flask, controlling the total volume to 100 mL~200 mL (if titrating in ethanol, the total volume shall not exceed 40 mL, with a volume ratio of ethanol to water of 3.1). Add 4~5 drops of bromophenol blue indicator solution (0.4 g/L), and adjust the pH of the test solution to 2.5~3.5 by following one of the following procedures. -- If the test solution is yellow, add sodium hydroxide solution until the test solution turns blue, then add nitric acid solution until the test solution just turns yellow, and then add more 2~6 drops (in the case of ethanol solution, add more 2~3 drops); -- If the test solution is blue, add nitric acid solution until the test solution is just yellow, and then add more 2~6 drops (in the case of ethanol solution, add more 2~3 drops). 5.4.2 Test Add 1 mL of diphenylcarbazone indicator solution (0.25 g/L) to the test solution and titrate with a mercuric nitrate standard titration solution of appropriate concentration (see Appendix B) until the color of the test solution changes from yellow to purple-red, that is, the end. At the same time, a blank test is also performed. Except that no sample is added to the blank test solution, the types and amounts of other reagents added (except the standard titration solution) are the same as those of the test solution. NOTE 1.During determination, the limits and elimination of some ions that do not interfere with the determination, ions that interfere with the determination, and co-existing interfering substances are shown in Appendix A and Appendix C, respectively. NOTE 2.Collect and retain the mercury-containing waste liquid after titration. See Appendix D for treatment methods. 5.5 Experimental data processing The chloride content is expressed as the mass fraction w of chloride (as Cl) and is calculated according to formula (1). Where V -- the volume of the mercuric nitrate standard titration solution consumed in the titration of the test solution, in milliliters (mL); V0 -- the volume of the mercuric nitrate standard titration solution consumed in the titration of the blank test solution, in milliliters (mL); c -- the exact value of the concentration of the mercuric nitrate standard titration solution, in moles per liter (mol/L); M -- the molar mass of chlorine (Cl), in grams per mole (g/mol) (M=35.45); m -- the mass of the specimen, in grams (g).6 Ion chromatography
6.1 Principle The test solution enters the anion exchange column and is eluted with the eluent. Chloride ions in the test solution undergo ion exchange on the anion exchange column and are carried to the detector by the eluent, forming a Gaussian-distribution chromatographic peak. The peak area/height of chloride (as Cl) within a certain concentration range is proportional to the component concentration, allowing the chloride content to be determined. 6.2 Reagents or materials 6.2.1 Chloride standard solution. 1 mL of solution contains 0.01 mg of chlorine (Cl). Pipette 1.00 mL of the chloride standard stock solution (as Cl) prepared according to HG/T 3696.2 into a 100 mL volumetric flask. Dilute to the mark with water and shake ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
