Determination of sulphite in wine samples with the aid of three different analytical techniques

Abstract

This study comparatively analyzed the free and total sulphite in thirty wine samples divided into alcoholic wines, non-alcoholic wines, and fruit juice wines using three analytical techniques, namely, the titrimetric method, the spectrophotometric technique, and the chromatographic technique (HPLC). All the wine samples using the three different analytical techniques were below the permissible limit of sulphite in wine samples as stated by regulatory bodies. Analyzing the free sulphite concentration in the wine samples gotten from the spectrophotometric analysis, it can be seen that alcoholic wine had the least free sulphite concentration (11.11 14.65 mg/10 ml). The total sulphite concentration was also found to be lowest in the alcoholic wine samples (24.49–33.62 mg/10 ml for the Spectrophotometric method; 31.21–39.26 mg/10 ml for the HPLC method; and 31–38.71 mg/10 ml for the titrimetric method). It was observed that fruit juice wines contain the highest concentration of sulphite (both free and total sulphite), followed by non-alcoholic wines, and then alcoholic wines. Statistical data analysis of the experimental results obtained for the study showed that the titrimetric technique had the highest accuracy for the determination of total sulphite in the three groups of samples, the spectrophotometric technique had the highest accuracy for the determination of free sulphite in alcoholic and non-alcoholic wines, and HPLC had the highest accuracy for the determination of free sulphite in fruit juice wines.