Dithiocarbamates as a sensitive electroanalytical reagent: determination of chromium by catalytic hydrogen wave at DME in water systems and vegetables.

摘要

Simple, sensitive catalytic hydrogen polarographic method was developed for the determination of chromium (VI) with ammonium piperidine dithiocarbamate (Amm Pip-DTC) and ammonium morpholine dithiocarbamate (Amm Mor-DTC) in various water systems and vegetables. The method was based on the catalytic hydrogen wave of Amm Pip-DTC-Cr(VI) and Amm Mor-DTC-Cr(VI) complexes in the presence of NH₄Cl-NH₄OH medium at pH 7.5 and 9.6 and produce a catalytic hydrogen waves at -1.59 and -1.65 V Vs SCE, respectively. Various optimum parameters such as effect of pH, NH₄Cl-NH₄OH, Pip-DTC, metal ion concentrations and excipient effect on peak height were investigated to enhance the sensitivity, selectivity, and detection limits of the present method and compared in terms of Students t test and variance ratio f test with differential pulse polarography (DPP) method. The proposed method was applied for the determination of chromium (VI) in various water system and vegetables and the results obtained were in good agreement with DPP.