High-performance liquid chromatographic determination of methanesulphinic acid as a method for the determination of hydroxyl radicals.

For the determination of hydroxyl radicals, dimethyl sulphoxide was used as a molecular probe and the methanesulphinic acid produced was determined by high-performance liquid chromatography of its Fast Yellow GC salt derivative. The results for hydroxyl radicals formed using the Fenton and hypoxanthine-xanthine oxidase systems agreed well with the theoretical values. Interferences from phenols, aromatic amines and amino acids, which give coloured substances by reaction with the diazonium salt, could be avoided. The recovery of methanesulphinic acid added to liver homogenates and incubated for 1 h at 37 degrees C was 70.2 +/- 2.1%. The detection limit for methanesulphinic acid in a sample solution was ca. 8 ng/ml.