VOLTAMMETRIC DETECTION OF MOO42- AT A MODIFIED CARBON-PASTE ELECTRODECONTAINING CHITIN

The voltammetric determination of MoO42- after accumulation on a carbo n paste electrode (CPE) modified with chitin was investigated. MoO42- can be selectively accumulated on the electrode based on the electrost atic interaction with the acetylamide group in chitin in 0.1 M acetate buffer (pH 4.3) without the need to apply a potential. The oxidation peak of molybdenum(IV) was observed at -0.58 V (vs. Ag/AgCl) in 0.1 M acetate buffer (pH 4.3) by scanning the potential in a positive direct ion. The calibration curve of MoO42- was linear in the range from 1 x 10(-7) to 5 x 10(-6) M for an accumulation of 20 min. Coexisting ions hardly affect the voltammetric measurement because the accumulation so lution differed from the measurement solution. The presented method wa s applied to the determination of MoO42- in sea water. (C) 1997 Elsevi er Science B.V.