An assay for ascorbic acid based on polyaniline-coated microplates

A technique for modification of the microtiter reader plates well with a po lyaniline (PANI) film sensitive for ascorbic acid is presented. The princip le of the analyte detection is based on monitoring the changes in optical a bsorption of the PANI film resulting from the reduction process initiated b y ascorbic acid. The detection limit for ascorbic acid is 1 mg/L. Testing w ith real samples (soft drinks, fruit juices) gave good correlation of the m ethod with iodimetric titration. High sensitivity, stability, and good repr oducibility of the measurements make the proposed system an attractive alte rnative to traditional assays, used in medicine, ecology and biotechnology.