A method for determining the content of lead and cadmium elements in silver ornaments

A technology of element content and silver jewelry, which is applied in the detection field of silver jewelry element content, can solve the problems of low content of lead and cadmium elements, inaccurate detection results, and inability to obtain accurate data, etc., achieving high recovery rate and good stability Effect

Active Publication Date: 2020-06-23
SHANDONG MEASUREMENT SCI RES INST
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, it has been reported in the literature that silver chloride precipitation has a strong adsorption capacity for lead and cadmium elements, resulting in inaccurate detection results.
Especially for children's silver jewelry, the content of lead and cadmium may be very low, and after the precipitation and adsorption of silver chloride, it is impossible to obtain accurate data

Method used

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  • A method for determining the content of lead and cadmium elements in silver ornaments
  • A method for determining the content of lead and cadmium elements in silver ornaments
  • A method for determining the content of lead and cadmium elements in silver ornaments

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Example 1: Adsorption experiment of lead and cadmium elements by silver chloride in the national standard GB / T 21198.5-2007 test method.

[0028] Prepare a mixed standard solution with a content of 50 μg / mL of lead and cadmium, and then use the mixed standard solution of lead and cadmium to prepare a series of mixed standards of lead and cadmium with a concentration of 0, 1.0, 2.0, 3.0, 5.0, and 10.0 μg / mL The solution is measured on the machine, and the appropriate curve equation is selected to establish a working curve.

[0029] Use nitric acid and high-purity silver (silver content higher than 99.99wt%) to prepare 50μg / mL silver-containing matrix solution, then measure 10.00mL of 50μg / mL silver-containing matrix solution and place it in a 50mL beaker, add 1.00, 5.00, 10.00mL respectively After adding 15mL of concentrated nitric acid, slowly heating to drive out the nitrogen oxides. Then slowly drop 2mL of 37wt% hydrochloric acid solution, after standing still for 2 ...

Embodiment 2

[0039] Embodiment 2: the experiment of measuring lead, cadmium element content in the silver solution by thiocyanate solution.

[0040] Prepare a mixed standard solution with a content of 50 μg / mL of lead and cadmium, and then use the mixed standard solution of lead and cadmium to prepare a series of mixed standards of lead and cadmium with a concentration of 0, 1.0, 2.0, 3.0, 5.0, and 10.0 μg / mL The solution is measured on the machine, and the appropriate curve equation is selected to establish a working curve.

[0041] Use nitric acid and high-purity silver (silver content higher than 99.99wt%) to prepare 50μg / mL silver-containing matrix solution, then measure 10.00mL of 50μg / mL silver-containing matrix solution and place it in a 50mL beaker, add 1.00, 5.00, 10.00mL respectively After adding 15mL of concentrated nitric acid to the standard solution of the mixed series of two elements, slowly heat to drive away the nitrogen oxides. Then slowly drop into 2mL of 0.25g / mL potas...

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Abstract

The invention relates to a method for determination of lead and cadmium content in silver jewelry and belongs to the field of precious metal analysis. The method comprises dissolving a silver sample to be detected through nitric acid to obtain a silver nitrate solution, adding a thiocyanate solution into the silver nitrate solution so that the silver nitrate is completely precipitated to form silver rhodanide, filtering to remove silver rhodanide precipitates, collecting the filtrate and determining lead and cadmium contents. Potassium thiocyanate is used as a precipitating agent and can solve the problem that lead and cadmium contents cannot be accurately determined because of silver chloride precipitate adsorption effects on lead and cadmium. The method realizes accurate determination of two element contents of silver jewelry.

Description

technical field [0001] The invention relates to a method for detecting element content of silver ornaments, in particular to a method for determining the content of lead and cadmium elements in silver ornaments. Background technique [0002] Lead and cadmium are common impurity elements in pure silver jewelry, and lead is more common. Lead impurities may be introduced from silver mining to processing into jewelry. Cadmium is often added to solder to reduce its melting point and fluidity. Both lead and cadmium are harmful elements. Lead can cause blood and nervous system disorders. Wearing lead-containing children's jewelry for a long time will cause children's blood lead to exceed the standard, causing ADHD and mania. Cadmium is toxic and causes bone damage. The national standard GB 28480-2012 stipulates that the lead content in jewelry shall not exceed 1000mg / kg, and the cadmium content shall not exceed 100mg / kg. For children's jewelry, the lead content shall not exceed 9...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N21/73
CPCG01N21/73
Inventor 李桂华刘雪松刘海彬于春宏王萍张凤霞白著双
Owner SHANDONG MEASUREMENT SCI RES INST
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