SPECTROPHOTOMETRIC DETERMINATION OF CHROMIUM BY OXIDATION OF PROCHLORPERAZINE DIMALEATE

摘要

A rapid and sensitive spectrophotometric method for the determination of chromium is presented,which is based on the oxidation of prochlorperazine dimaleate (PCPM)by chromium(VI)in orthophosphoric acid medium.The reagent forms a red coloured radical cation instantaneously at room temperature.The red species exhibits an absorption maximum at 535 nm with a molar absorptivity and the Sandell's sensitivity of 2.09 x 10~4 l mol~(-1)cm~(-1)and 2.48 ng cm4,respectively.The colour developed is stable for 2 h,and the Beer's law obeyed over a concentration range 0.2 to 2 mu g ml-1 chromium(VI).The detection limit of chromium(VI)is 40 ng ml-1.Chromium(III)can be determined after it is oxidised with bromine water in alkaline medium to chromium(VI).All variables were studied in order to optimise the reaction conditions.The proposed method has been successfully applied to the determination of chromium in alloy steels,industrial effluents,pharmaceutical preparations,soil and water.