A rapid distillation method coupled with ion chromatography for the determination of total sulphur dioxide in foods

A rapid distillation method coupled with ion chromatography for the determination of total sulphur dioxide in foods was developed. The distillation was performed using vapour and carbon dioxide stream released from the reaction between sodium carbonate and sulphuric acid. The distilled product was captured in sodium hydroxide solution and sulphur dioxide was measured as sulphite by ion chromatography. The linearity ranged from 0.051 to 32.1 mg L−1 SO2 and limit of detection was 0.013 mg L−1. This method was successfully applied to the determination of total sulphur dioxide in preserved foods, dried vegetables, vermicelli and wines. The recovery ranged from 76.7% to 104.8% with the relative standard deviation of 0.7–8.2%. The distillation procedure was rapidly achieved within 3 min without blowing nitrogen or air. The method presented advantages of time-saving and simplification working process compared to the conventional method and is already used as China National Standard Method.