FLOW-INJECTION AMPEROMETRIC DETECTION OF ANILINE WITH A PEROXIDASE MODIFIED CARBON-PASTE ELECTRODE

A horseradish peroxidase modified carbon paste electrode, useful for t he determination of aniline at low ppb levels, is described. The enzym e was dispersed in the carbon paste and immobilised on a Nafion membra ne. Cyclic voltammetry and differential pulse polarography were used t o characterise the enzymatic electrochemical process, and several reac tion products were identified. The electrode has been utilised for the flow injection amperometric detection of aniline at potentials down t o + 100 mV (Ag/AgCl), giving fast responses (t < 30 s), a measurement precision of 0.75% R.S.D. (n = 8) and a sampling frequency of 20 h(-1) . Application of the electrode to the analysis of aniline in spiked ve getable oil samples, using liquid-liquid extraction, resulted in a pro cedure giving no matrix interferences and a mean recovery of 99.4 +/- 3.2%.