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GB/T 28021-2011 PDF English

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GB/T 28021-2011: Adornment -- Determination of baneful elements -- Method of spectrometry
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GB/T 28021-2011: Adornment -- Determination of baneful elements -- Method of spectrometry

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GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 39.060 Y 88 Adornment - Determination of Baneful Elements - Method of Spectrometry Issued on. OCTOBER 31, 2011 Implemented on. FEBRUARY 01, 2012 Issued by. General Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China; Standardization Administration of the People's Republic of China.

Table of Contents

Foreword... 3 1 Scope... 4 2 Normative References... 4 3 Principles... 4 4 Reagents... 4 5 Apparatuses... 5 6 Determination of Baneful Elements’ Content... 5 7 Determination of Baneful Elements’ Dissolution Quantity... 9 8 Test report...11

Foreword

This Standard was drafted according to the rules specified in GB/T 1.1-2009. This Standard was proposed by China National Light Industry Council. This Standard shall be under the jurisdiction of National Standardization Technical Committee of Jewelry (SAC/TC 256). Drafting organization of this Standard. National Jewelry Quality Supervision and Inspection Center. Chief drafting staffs of this Standard. Li Suqing, Li Yuou and Li Wujun. Adornment - Determination of Baneful Elements – Method of Spectrometry

1 Scope

This Standard specifies the method of spectrometry to determine content and dissolution quantity of baneful elements in adornment. This Standard is applicable to determination of content and dissolution quantity of baneful elements in adornment.

2 Normative References

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any modification sheet) applies. GB 28480 "Adornment - Provision for Limit of Baneful Elements"

3 Principles

As for adornments made of metal material, they are directly processed with conventional acid digestion method; as for adornments made of other materials, they are processed with enclosed high-temperature pressure tank - acid digestion method. The arsenic, lead, mercury and cadmium in the sample thus become soluble salts, and are dissolved in the acid digestion solution. After volumetrically scaling the digestion solution, determine them with flame atomic absorption spectrometric method and inductively-coupled plasma spectrometry.

4 Reagents

Unless otherwise specified, only identified analytical reagent AND distilled water, or deionized water, or water with equivalent purity are to be used in the analysis. 4.1 Nitric acid, with a mass fraction of 65% ~ 68%, and density ρ of 1.40 g/mL. 4.2 Nitric acid, (1+1). 4.3 Hydrochloric acid, with a mass fraction of 36%~38%, and density ρ of 1.19g/mL. 4.4 Hydrochloric acid, (0.07 ± 0.005) mol/L, (1+169). 4.8 Hydrofluoric acid. 4.9 Stibium, arsenic, barium, cadmium, chromium, lead, mercury and selenium standard stock solution, 100 mg/L~1000 mg/L.

5 Apparatuses

Normal laboratory apparatuses and the following apparatuses. 5.1 Analytical spectrometer. The apparatus, after being optimized, may meet the following requirements. 5.2 Oven. 0°C~ 200°C, with a temperature control accuracy of ± 2°C. 5.3 Pressure tank. Polytetrafluoroethylene pressure tank or stainless steel pressure tank (polytetrafluoroethylene liner). 5.0 times of the extraction agent for hydrochloric acid solution.

6 Determination of Baneful Elements’ Content

6.1 Sample preparation 6.2 Digestion of sample 6.2.1 Conventional acid digestion method This method is applicable to samples specified in 6.1.1. Weigh 0.3g~0.5g of samples for two portions, accurate to 0.1 mg; place them in the beaker or conical flask. 6.2.2 Pressure tank digestion method This method is applicable to samples specified in 6.1.2. Weigh 0.3g~0.5g of samples for two portions, accurate to 0.1 mg; place them in pressure tank (5.3); add 8 ml of nitric acid (4.1) and 2mL of hydrogen peroxide (4.7); as for materials such as glass and ceramics with many silicon, re-add 3 ml of hydrofluoric acid (4.8); cover it with a watch glass; tighten up; place it in an oven (5.2); heat for 4h at 180°C ±5°C. 6.2.3 Other digestion methods After being verified and feasible, other digestion methods such as microwave digestion, acid wet digestion, ashing method may be selected to process the samples specified in 6.1.2; and adopt the samples that fail to completely digest by method specified in 6.2.1. 6.3 Determination 6.3.1 AAS method 6.3.2.2 Preliminary test Confirm the approximate content of each impurity elements in sample solution. The concentration of to-be-tested element in calibration solutions shall not be less than the actual concentration of element in sample solution. 6.3.2.3 Accurate determination According to the test result of 6.3.2.2, respectively add the standard stock solutions (4.9) of the tested elements into 100 ml volumetric flasks; dilute to the scale with aqua regia (4.6); then shake well and prepare the high/low standard calibration solutions. The concentration interval between the tested elements in high/low standard solutions. cadmium not greater than 5 mg/L, other elements not greater than 20 mg/L. Determine the sample solution (6.2) and calibration solution with plasma spectrometer. Use the aqua regia (4.6) as the "zero point" calibration solution. 6.4 Expression of results The content of arsenic, lead, mercury and cadmium in samples is counted by mass fraction w, the value is expressed by mg/kg, and is calculated according to Formula

7 Determination of Baneful Elements’ Dissolution Quantity

7.1 Preparation of extracting solution Weigh the to-be-tested sample with an analytical balance (5.4), accurate to 0.1 mg; place it in an appropriate covered container (5.6); add sufficient hydrochloric acid solution (4.4) with a temperature of 37°C±2°C; make sure that the sample is exactly immersed into the solution. Cover the container; place it in an oven (5.2) which can control the temperature for 2h at 37°C±2°C. 7.2 Determination Determine the concentration of stibium, barium, selenium, arsenic, lead, mercury, cadmium or chromium extracting solution (7.1) with analytical spectrometer (5.1) and according to the method specified in 6.3, that is to say, the hydrochloric acid (4.4) is as zero point correction solution and fix-volume solution. 7.3 Expression of results 7.3.1 Calculation of baneful elements dissolution quantity The dissolution quantity of baneful elements in sample is counted by mass fraction w, the value is expressed by mg/kg and is calculated according to Formula (2). 7.3.2 Interpretation of results Because of precision of test method specified in this Standard, when considering the test results between laboratories, a corrected analytical result is needed. The analysis result calculated in 7.3.1 shall deduct the analysis correction value in Table 1, so as to obtain the analysis result after correcting.

8 Test report

The test report shall at least include the following information.

Appendix A

(Informative) Recommended Analytical Test Line The recommended wavelength of each element is detailed in Table A.1. ......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.


      

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