Amperometric biosensor for ascorbic acid

• Autor(a) principal: Tomita,I. N.
• Data de Publicação: 2005
• Outros Autores: Manzoli,A., Fertonani,F. L., Yamanaka,H.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Eclética Química
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-46702005000200005
• topic: biosensor; ascorbic acid; flow injection analysis

A L-ascorbic acid biosensor based on ascorbate oxidase has been developed. The enzyme was extracted from the mesocarp of cucumber (Cucumis sativus) by using 0.05 mol L-1 phosphate buffer, pH 5.8 containing 0.5 mol L-1 NaCl. After the dialysis versus phosphate buffer 0.05 mol L-1 pH 5.8, the enzyme was immobilized onto nylon net through glutaraldehyde covalent bond. The membrane was coupled to an O2 electrode and the yielding reaction monitored by oxygen depletion at -600 mV using flow injection analysis optimized to 0.1 mol L-1 phosphate buffer pH 5.8, as the carrier solution and flow-rate of 0.5 mL min-1. The ascorbic acid calibration curve was linear from 1.2x10-4 to 1.0x10-3 mol L-1. The evaluation of biosensor lifetime leads to 500 injections. Commercial pharmaceutical samples were analyzed with the proposed method and the results were compared with those obtained by high-performance liquid chromatography (HPLC).