A fill and flow channel biosensor with a predictor electrode
was developed to determine sulfite. The basis of determination
is the current difference between predictor and
detector electrodes. This strategy can efficiently correct for
the interfering current at the detector electrode. Acceptable
repeatability (R.S.D. < 10%) was obtained. The interferences
of ethanol, ascorbic acid, sorbic acid and tartaric acid were
investigated. Experimental results indicated that the measured
sulfite concentrations were in good agreement with
spiked values. Finally, this method was used to determine
sulfite in a beer sample. The detected concentrations were
compared with values obtained from a reference method
based on the Monier–Williams method.