[Migration behavior and toxicology of methyltin stabilizers]

With a view to studying the possible use of methyltin compounds as PVC stabilizers in food industry, the authors elaborated a method for the thin-layer chromatographic and subsequent spectrophotometric or polarographic determination of mono-, di- and trimethyltin compounds in the stabilizer and after migration. Monmethyltin compounds are determined spectrophotometrically after reaction with quercetin. Dimethyltin compounds are incinerated by the wet method using sulphuric and nitric acids, and inorganic tin is then estimated polarographically. Prior to identification trimethyltin compounds must be converted into dimethyltin compounds by ultraviolet irradiation or by treatment with triethylamine and bromine. Corresponding to the different conditions of use, the authors investigated the migration of the methyltin stabilizer from PVC into distilled water, 3% acetic acid, 20% alcohol, 50% alcohol und Fettsimulans HB 307. They stated that its tendency to migration into foods is not greater than that of the octyltin stabilizer. The experimentally obtained migration values are discussed in connexion with toxicological data.