Analysis of residual vulcanization accelerators in baby bottle rubber teats

An analytical method was established for the determination of dialkyldithiocarbamates (DTCs) in chloroform-acetone extracts from rubber teats for baby bottles. DTCs in the extracts were derivatized into ethyl esters and analysed by gas chromatography employing nitrogen-phosphorus detection. Dimethyldithiocarbamate and diethyldithiocarbamate were detected at levels up to 3.2 micrograms/g rubber and up to 4.6 micrograms/g rubber (as dithiocarbamic acid), respectively, in the extracts from commercially available isoprene rubber tests. DTCs can form secondary amines by acid hydrolysis, although the levels of DTCs in the extracts only made a minor contribution to the total level of measured secondary amine precursors.