Determination of Total Sulphur Dioxide in Beer Samples by Flow-Through Chronopotentiometry

Abstract

A chronopotentiometric method for the determination of total sulphur dioxide in beer is described. Free and bound sulphites were converted to sulphite anions on alkalising the sample solutions. On acidifying the solution, the released sulphur dioxide was on-line separated through a semipermeable membrane and transported by an electrolyte into the measuring cell and measured by stripping chronopotentiometry. The proposed method was validated and compared with the three EBC methods. The RSD of repeatability was 8.6% for the normal SO2 level in the beer (3.4 mg/L). The results corresponded well with those obtained with the alternative EBC methods. The elaborated method was much faster and simpler than the EBC methods.