Determination of phenolic acids using Trametes versicolor laccase

Two biosensors based on Trametes versicolor laccase (TvL) were developed for the determination of phenolic compounds. Commercial oxygen electrode and ferrocene-modified screen-printed graphite electrodes were used for preparation of laccase biosensors. The systems were calibrated for three phenolic acids. Linearity was obtained in the concentration range 0.1–1.0 μM caffeic acid, 0.05–0.2 μM ferulic acid, 2.0–14.0 μM syringic acid for laccase immobilised on a commercial oxygen electrode and 2.0–30.0 μM caffeic acid, 2.0–10.0 μM ferulic acid, 4.0–30.0 μM syringic acid for laccase immobilised on ferrocene-modified screen-printed electrodes. Furthermore, optimal pH, temperature and thermal stability studies were performed with the commercial oxygen electrode. Both electrodes were used for determination of a class of phenolic acids, achieving a cheap and fast tool and an easy to be used procedure for screening real samples of human plasma.