MODIFIED SOLID ELECTRODES FOR STRIPPING VOLTAMMETRIC DETERMINATION OFTIN

The paper describes the determination of tin by ASV using modified thi ck film electrodes. Three different types of electrodes were developed : One modified with a mixture of Nafion and mercury(II)acetate, one mo dified with diethyldithiocarbamate (DDC) or pyrrolidinedithiocarbamate (PDC) and mercury(II)acetate, and one modified with calomel. The anal yte was accumulated on the electrode surface after special electrochem ical pretreatment of the modified electrode. After recording the volta mmogram the electrodes were electrochemically regenerated. By virtue o f their lifetime and their measurement reproducibility, we preferred t he DDC and PDC modified electrodes. They can be used for months withou t changing their chemical characteristics. The linear range for tin de termination with these electrodes is between 1 and 100 mu g/L; the det ection limit was calculated as 0.9 mu g/L. The electrodes were applied to the direct determination of tin in different canned fruit juices w ithout special sample pretreatment.