Ascorbic acid determination with an ion-sensitive field effect transistor-based peroxidase biosensor

Horseradish peroxidase immobilized on the surface of an Ion Sensitive Field Effect Transistor (ISFET) can be used for the determination of l-ascorbic acid in fruit juices and beverages. The influence of buffer concentration, pH and ionic strength on sensor performance in phosphate and citrate buffers was examined. Vitamin C contents in the samples have also been determined by liquid chromatography. Correlation between the two analytical methods, obtained for the samples with relatively high (1 mM or more) ascorbic acid concentration, allows to consider the present biosensor as a promising detector for routine vitamin C determination.