The general principle of postcolumn derivatization and its advantagesinfoodanalysiswasthoroughlydescribedbyGalensain the book “Food Biosensor Analysis” (Wagner and Guilbault, 1994). In his working group, the specific coupling of an HPLC system with an integrated sulfite oxidase reactor between the column and the detector was first described in the dissertation thesis of Pabel (1993). Several modifications and advancements of the method werelaterpresentedbyWeßels(Weßelsetal.,1995;Weßels,1997) again in the working group of Galensa. Further optimization of the method was presented by Patz et al. (1997).