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

A horseradish peroxidase modified carbon paste electrode, useful for the determination of aniline at low ppb levels, is described. The enzyme was dispersed in the carbon paste and immobilised on a Nafion membrane. Cyclic voltammetry and differential pulse polarography were used to characterise the enzymatic electrochemical process, and several reaction products were identified. The electrode has been utilised for the flow injection amperometric detection of aniline at potentials down to + 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 vegetable oil samples, using liquid-liquid extraction, resulted in a procedure giving no matrix interferences and a mean recovery of 99.4 +/- 3.2%.