Inanotherexperiment,thedataandstatisticsobtainedfromthe analyses of two grape juices were determined. Not only does the enzyme-based method yield higher results, the HPLC–IMER also shows better reproducibility, when comparing the method param-eters variance, standard deviation and relative standard deviation of both methods. For example, the relative standard deviation of the HPLC–IMER was 1.68% for a red grape juice and 2.36% for a white grape juice. In contrast, the relative standard deviation of the IFU 7a was 8.79% for a red grape juice and 7.04% for a white grape juice. Especially in the low concentration range of about 10mg/L SO2, a good reproducibility of the method is essential for a reliable judgment of the marketability of the products.