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This standard is the revision of "Methods for Chemical Analysis of Precious Metals Alloys - General Rules" (YS/T 371-1994).
Compared with YS/T 371-1994, the main changes in this standard are as follows:
- Foreword is added.
- Contents regarding application scope of standard are added.
- Contents of the original general rules are enriched.
- Regulations of methods for chemical analysis of precious metals alloys are added.
Appendix A of this standard is normative.
This standard supersedes YS/T 371-1994 from the implementation date hereof.
This standard is proposed by and is under the jurisdiction of National Technical Committee on Nonferrous Metals of Standardization Administration of China.
Chief drafting organization of this standard: Sino-platinum Metals Co., Ltd.
Chief drafting staff of this standard: Fang Wei and Shi Hong.
The National Technical Committee on Nonferrous Metals of Standardization Administration of China is in charge of the explanation of this standard.
The previous editions of the standard superseded by this standard are as follows:
- YB 946-78;
- YS/T 371-1994.
Methods for Chemical Analysis of Precious Metals Alloys - General Rules and Regulations
貴金屬合金化學(xué)分析方法
總則及一般規(guī)定
1 Scope
This standard specifies the general rules and regulations of methods for chemical analysis of precious metals alloys.
This standard is applicable to the preparation of formulation (revision) of methods for chemical analysis of precious metals alloys.
2 Normative References
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments to (excluding amending errors in the text), or revisions of, any of these publications do not apply. However, all parties coming to an agreement according to this standard are encouraged to study whether the latest edition of the normative document is applicable. For undated references, the latest edition of the normative document applies.
GB/T 3100 The International System of Units and its Application
GB/T 3101 General Principles Concerning Quantities, Units and Symbols
GB/T 3102 Quantities and Units (All Parts)
GB/T 8170 Rules for Rounding off of Numerical Values
GB/T 6379 Precision of Test Methods - Determination of Repeatability and Reproducibility for a Standard Test Method by Interlaboratory Tests
3 General Rules
3.1 This standard is applicable to the standards regarding the methods for chemical analysis of precious metals alloys, and the formulation (revision) of such standards shall comply with this standard. Contents in this standard may be regarded as arbitration analysis and accurate analysis methods and may be used upon verification of other analysis methods and deterministic analysis of standard substance.
3.2 Standards regarding methods for chemical analysis of precious metals alloys shall be formulated (revised) according to elements or analysis items after proper product classification, and they are not respectively formulated (revised) according to the alloy type or its designation. For example, the standard regarding the methods for chemical analysis of argentum shall be applicable to the analysis of Ag in such alloys as AgCu, AgCuNi, AgCe and AgNi.
3.3 In standards regarding methods for chemical analysis of precious metals alloys, the lower limit of analysis in the determination range of each element shall be 1~3 times lower than that of chemical composition of product, while the upper limit of analysis shall be 1 time higher than that of the chemical composition of product.
3.4 A standard method of analysis is established for the same element. Where a standard method of analysis cannot satisfy the determination range or application scope, standard method of analysis may be separately established. Two or more standard methods of analysis shall not be established for the same determination range and application scope.
3.5 Standards regarding methods for chemical analysis of precious metals alloys shall include: foreword, introduction, standard name, warning, scope, normative references, method summary (or principle), reagents and materials, instruments and equipment, analysis procedures, result calculation, precision, test report, appendixes, references, etc.
3.5.1 Foreword: if applicable, major differences compared with the former edition shall be provided; for the standard divided into parts, the name of each part shall be provided.
3.5.2 Introduction: optional; if necessary, it may be used to express additional information, e.g. describe relevant technical contents of the standard and its causes for formulation.
3.5.3 Standard name: shall briefly and accurately express the applicable product of the test method, the designated component to be determined and the property of determination method. Contents of standard name should not beyond the above three elements.
Example: Determination of Copper Content in Precious Metals and Their Alloys - Complexometric Titration
3.5.4 Warning: attention must be attached to the analyzed products and reagents or analysis procedures which are hazardous or harmful to health or environment. These contents shall be printed and arranged in bold type.
- If the hazard belongs to general warning or comes from the analyzed product, it shall be immediately indicated in the standard name;
- If the hazard comes from special reagent or material, it shall be indicated following the name of reagent or material;
- If the hazard is inherent in analysis procedure, it shall be indicated at the beginning of the "Analysis Procedures" chapter.
3.5.5 Normative references: if available, schedule of normative references shall be listed in standard.
3.5.6 Method summary (or principle): it shall describe the application scope, determination range as well as the limit and interference elimination method of potential interference element in addition to briefly expressing the major analysis procedures and conditions (where necessary, the method principle shall be described with balanced reaction).
3.5.7 Reagents and materials: the names of reagents, except indicators and organic dyes, shall be written out according to systematic nomenclature, and then the trivial names are written in parentheses following the names determined according to systematic nomenclature; trivial names only may be adopted where appear in other parts. Trade name shall be avoided. Reagents are arranged in the following sequence:
- Products used in commercially available state (excluding solution);
- Solution and suspension liquids (excluding standard titration solutions and standard solutions).
- Standard titration solutions and standard solutions;
- Indicators;
- Auxiliary materials (desiccant, etc.).
3.5.8 Instruments and equipment: the names, main performance and technical indexes of instruments and equipment used during analysis or test (except ordinary laboratory instruments) shall be listed. All those meeting relevant requirements may be adopted.
3.5.9 Analysis procedures: the number of clauses in this part is equal to the number of operations or serial operations. Each serial operation shall be exactly and briefly stated in imperative sentences.
3.5.10 Result calculation: indicate the result calculation method (including unit, formula, symbol meaning, significant digits, etc.).
3.5.11 Precision: precision data (e.g. repeatability and reproducibility) shall be indicated for the method with interlaboratory test.
3.5.12 Test report: contents which shall be covered are method principle, sample dissolution, selection of determination conditions, interfering ion limit, elimination method once exceeding the limit, result calculation, method precision, accuracy (inspection with standard sample is preferred; where standard sample is unavailable, contrast analysis with similar domestic and foreign standard methods or other good methods may be carried out; if neither is practical, addition recovery test is carried out to provide accuracy assessment data), operation procedures of analysis method and references.
3.5.13 Appendix: if it is convenient to express the standard details in form of appendix, and this can make the test simpler, appendix may be adopted. Whether the appendix is "normative" or "informative" shall be indicated.
3.5.14 References: where informative references are required, they may be provided in corresponding position in the text through quotation; where there are various informative references, they may be listed in the "References" at the end of this text.
3.6 The data obtained through measurement and metering according to standards regarding methods for chemical analysis of precious metals alloys, the mass, volume and etc. shall be expressed with significant digits like 0.1000g and 10.00mL according to the actual precision of instruments and containers adopted for analysis work.
3.7 Rounding off method for numerical values is implemented according to GB/T 8170.
3.8 The latest atomic weight shall be adopted for the formulation (revision) of standards regarding methods for chemical analysis of precious metals alloys.
3.9 Quantities, units and symbols of substances are implemented according to the requirements of GB/T 3100, GB/T 3101 and GB/T 3102 (All Parts).
3.10 Precision test is subject to statistical treatment according to GB/T 6379.
3.11 The sampling and preparation of samples for chemical composition analysis of precious metals alloys shall be implemented according to relevant standards and technical requirements.
4 Regulations
4.1 Unless otherwise specified, all water adopted during solution preparation and sample analysis refers to distilled water or deionized water with equivalent purity.
4.2 Unless otherwise specified, all reagents adopted in this standard refer to the analytical reagents meeting national standard or professional standard. Where reagent of other specification, eg. guaranteed reagent, is adopted, the specification of such reagent shall be indicated behind the reagent. Where it is ensured that the determination accuracy cannot be degraded, reagents of other purity grade may also be adopted. Where the reagent is voluntarily purified and synthesized by laboratory, the purification and synthetic method and the inspection method shall be specified.
Reference reagents shall be adopted for the reagents used as reference.
4.3 The liquid reagents like acid, ammonia water and hydrogen peroxide listed in this standard, where only with name specified, refer to the strong solutions of such reagents, and the mass concentration shall be indicated in the parentheses following the reagent name. For solid reagent containing crystal water, molecular formula shall be indicated in the parentheses following its name.
4.4 Special attention shall be paid to the safe use of flammable, explosive and toxic reagents which are liable to burn, like hydrofluoric acid, perchloric acid, mercury, beryllium, cyanide, benzene, methylbenzene and hydrogen peroxide.
4.5 All solutions listed in standards for analysis, unless those with solvents indicated, refer to aqueous solution.
4.6 The mass fraction of metal, where adopted for preparation of standard solution, is not less than 99.99%. The compound, where adopted for preparation of standard solution, shall be calibrated. Generally, the concentration of standard solution is expressed in mol/L and mol/mL. For the standard solution to be calibrated, the calibration method, calibration copies and permissible range value (the average cannot be taken once this value is exceeded, and same copies shall be prepared again for recalibration) shall be indicated below the name and preparation method of standard solution.
4.7 Products of Grade A (or Grade I) as specified in national standard shall be adopted for volumetric apparatus (titration flask, burette, pipette, colorimetric tube and etc.), and shall be periodically calibrated according to the relevant national provisions and regulations.
4.8 All operations in analytical method standard, unless otherwise specified, are carried out in glass wares. Hard glass container is adopted for the preparation and storage of reagent solution. For reagent solution corrosive to glass or those liable to dissolution, the material of storage container, precautions during storage and storage period shall be indicated, e.g. "polyethylene plastic bottle", "prepared immediately before use", "stored in brown bottle in dark place", etc.
4.9 The following are the expression modes of common solution concentration in standards:
4.9.1 The mass concentration of substance B: the mass of substance B divided by the total volume of the mixture. The measuring symbol is ρB. In analytical chemistry, it is usually expressed in g/L, mg/L, mg/mL, μg/mL or ng/mL etc.
4.9.2 The amount-of-substance concentration or concentration of substance B: the amount of substance B divided by the total volume of the mixture. The measuring symbol is cB. In analytical chemistry, it is usually expressed in mol/L and mol/mL. The basic unit type of solute must be indicated in practical applications.
4.9.3 The mass fraction of substance B: the mass ratio of solute to solution (solute and solvent), namely the mass ratio of substance B to mixture. The measuring symbol is ω. It is commonly expressed with "%", 10-6, 10-9, etc.
4.9.4 The volume fraction of substance B: the volume ratio of pure substance B to mixture under the same temperature and pressure. The measuring symbol is φB.
4.10 Volume ratio: refers to the ratio of liquid reagent to solvent.
4.11 Temperature: expressed in centigrade temperature scale (℃).
The standard temperature is 20℃. Generally, normal temperature refers to 15~25℃ while room temperature refers to 1~35℃. Unless otherwise specified, the temperature of cool place refers to 1~15℃ while that of warm water or solution is 40~60℃; the hot water is higher than 60℃ while the cold water is below 15℃. [GB/T 17418.1-1998].
4.12 In the analytical method standard, the conversion factor and the concentration of standard volumetric solution in the calculation formula of gravimetric method shall be reserved by four significant figures.
4.13 The weighed sample amount listed in the standard is suitable to general condition. The sample amount may be increased or decreased according to the content of the measured elements in the sample so as to control the measured element within the optimal measuring range.
4.14 2~3 determinations shall be independently carried out in order to ensure the analysis mass; the number of arbitration analysis determinations is not less than 5.
4.15 Measuring instruments of different models are allowable to be used in the standard; however, the stability performance and linear relation of the instruments shall be inspected according to the working condition of the adopted instrument before the sample determination; and the inspecting measurement shall be carried out with standard sample and may be used only after being determined as error-free.
4.16 Unless otherwise specified, the sensibility of balance adopted for the analysis shall reach 0.1mg. The balance and weights shall be periodically inspected and calibrated by metrological service. The sensibility shall be indicated where there are special requirements for balance.
Foreword I
1 Scope
2 Normative References
3 General Rules
4 Regulations
Appendix A (Normative) Tube Sealing Chlorination Dissolution Method for Indissoluble Platinum Group Metal and its Alloy Sample
References
