Differential pulse polargraphic determination of trace selenium (IV)and molybdenum(VI)using the catalytic hydrogen wave

摘要

In the presence of selenium(IV) and molybdenum(VI) a new polarographic peak appears which corresponds to a hydrogen catalytic wave. By differential pulse polarography a single, sharp peak at about -1.1V is obtained, allowing trace determination of selenium(IV) and molybdenum(VI) in the range 1*10~(-6)-5.0*10~(-9)M with a linear calibration and a detection llimit of 1.5*10~(-9)M. The optimum conditions are found to be 0.1M KNO_3 and a pH of about 3.2(Britton-Robinson buffer). THere is no serious interference from some ions when present at 1.0-40 times that of molybdenum. At higher amounts of interfering ions the interference is eliminated by the addition of EDTA.