SPECTROPHOTOMETRIC FLOW-THROUGH SENSOR FOR THE DETERMINATION OF SULFUR-DIOXIDE

Abstract

A continuous-flow sensor based on integrated separation and spectrophotometric detection was developed for the determination of sulphur dioxide at the ng ml-1 level by transient immobilization of the reaction product formed between p-rosaniline, formaldehyde and sulphur dioxide on an ion exchange support packed in a flow cell. Sulphur dioxide was thus determined in the range 0.16-6.0 mug ml-1 with a relative standard deviation of 2-3% (n = 11). The detection limit (3sigma) achieved was 49 ng ml-1. The proposed sensor was applied to the determination of free sulphur dioxide in white and rose wines and the results obtained were consistent with those provided by the EEC recommended method.