Indirect complexometric determination of mercury(II) using 1-propane thiol (PT) as a selective masking agent

摘要

A complexometric method for the determination of mer-cury(II) in presence of other metal ions is described based on the selective masking action of 1-propane thiol towards mercury(II).Mercury(II) present in a given sample solution is first complexed with an excess of EDTA and the unreacted EDTA is titrated against lead nitrate solution at pH 5-6 (hexamine buffer) using xylenol orange as the indicator.A 0.8% aqueous solution of 1-propane thiol is then added to displace EDTA from the Hg(II)-EDTA complex.The released EDTA is titrated with standard lead nitrate solution as before.Reproducible and accurate results are obtained for 4-85 mg of mercury(II),with relative error less than +-0.23 % and coefficient of variation not more than +-0.41 %.The effects of various ions were studied.The method is used for the analysis of mercury(II) in its synthetic alloy mixtures and also in complexes.