Use of a membraneless extraction module for the voltammetric determination of total sulfites in wine

A recently developed membraneless extraction module (MLEM) for sample preparation aiming the analysis of volatile and semi-volatile compounds is applied in the voltammetric analysis of total sulfites in wine. Square-wave voltammetry (SWV) is very advantageous in this case because sulfur dioxide (SO2) is instrumentally directly detected. The developed method shows good repeatability (RSD lower than 5%) and linearity (between 20 to 220 mg l–1) as well as suitable limits of detection (6 mg l–1) and quantification (19 mg l–1). The proposed method was also compared with the reference methodology (an iodimetry, the Ripper method) showing no significant differences in the obtained results.