부산대학교 도서관

A simple biosensor constructed by bulk-modification of carbon ink with manganese dioxide as a mediator was investigated for its ability to serve as amperometric detector for L-ascorbic acid in hydrodynamic mode. The sensor could be operated at pH 5.0 (0.05 M phosphate buffer) and exhibited excellent reproducibility and stability. Optimization of measurement parameters such as applied working potential and pH value were studied in detail. The screen printed electrode exhibited a linear amperometric increase with the concentration of L-ascorbic acid from 50 mg [L.sup.-1] to 250 mg [L.sup.-1] and gave a (LOD = 3[sigma]) detection limit of 0.2 mg [L.sup.-1] (1.172 [micro]mol [L.sup.-1]). The manganese dioxide modified screen printed electrode shows long term stability.
Introduction It is established that the oxidation of ascorbic acid (1) at low pH proceeds via two consecutive one-electron processes involving the participation of a radical anion intermediate (2) (the [...]