Determination of heavy metals in organic chemical products. Visual colorimetric method

1 Scope

This standard specifies the test method for the determination of heavy metals in organic chemical products by visual colorimetry

The wood standard is suitable for samples with heavy metal content (calculated as Pb) of 0.

2 Normative references

The clauses in the following documents have become clauses of this standard after being quoted in this standard

Preparation of GB/T602-2002 Standard Solution for Determination of Impurities in Chemical Reagents

Preparation of preparations and products used in GB/T603-2002 chemical reagent test method

GB/T6682-1992 Analytical laboratory water specifications and test methods (neqISO3696: 1987)

3 Principle

In a weakly acidic solution, the heavy metals copper, lead, and mercury are plasma-precipitated into corresponding sulfides with a saturated aqueous solution of hydrogen sulfide, and the color produced is compared with the standard color by visual method

4 Warning

Some test procedures specified in the test method may lead to dangerous situations, and the operator should take appropriate safety and protective measures

5 Reagents

Unless otherwise specified, only reagents confirmed to be analytically pure and grade 3 water specified in GB/T6682-1992 are used in the analysis

The standard solutions, preparations and products used in the analysis for impurity determination shall be prepared in accordance with the provisions of GB/T602-2002 and GB/T603-2002 when other requirements are not specified

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6 Instruments

General laboratory equipment and two matching 50mL colorimetric tubes

7 Analysis steps

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8 Results presentation

The color of the sample solution is not deeper than that of the standard colorimetric solution, and the heavy metal content (in terms of Pb) in the sample is qualified
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Related Links: Determination of Ignition Residues of Organic Chemical Products