PHASE-SELECTIVE ALTERNATING-CURRENT ADSORPTIVE STRIPPING VOLTAMMETRY OF FOLIC-ACID ON A MERCURY THIN-FILM ELECTRODE

Optimum conditions for the mercury electrodeposition onto glassy carbon electrodes and the optimum alternating current (AC) adsorptive stripping signals of folic acid (vitamin B-12) were found. The film was characterized by electron microscopy and the results obtained in the analysis of the vitamin were compared with those previously reported using conventional mercury electrodes (static or hanging). The mercury thin film electrode (MTFE) has shown more sensitive signals for folic acid with good performance and reproducibility. A detection limit down to 10(-12) M could be reached by using 300 s accumulation time.