how to determination zinc content in zinc sulfate?

by Thunder Tang Rech Chemical Co. Ltd

Rech Chemical Co. LTD is manufacturer of zinc sulfate in China, current produce zinc sulfate monohydrate powder 35% and zinc sulphate heptahydrate with zinc content 21.5. Some customers inquiry, asked how to determination zinc content in zinc sulfate?

Materials containing zinc zinc content in common EDTA coordination titration method for determination of zinc sulfate. The main principle is in zinc sulfate solution to add ammonium fluoride (sodium fluoride) and potassium hydroxide can join the oxidation (into three price to remove impurities such as Fe iron interference. In PH5 ~ 6 conditions to two cresol orange for indicator, with ethylenediamine tetraacetate two sodium standard titrate solution titration, the color by magenta into lemon yellow.

Finally through the calculated, EDTA standard titrate solution concentration and zinc sulfate zinc content in quality score (%).