Direct determination of butyl- and phenyltin compounds as chlorides using gas chromatography and flame photometric detection
Résumé
The simultaneous determination of butyl- and phenyltin chlorides using GC with flame photometric detection, which appears to be attractive because of its simplicity and rapidity in comparison with methods including a derivatization step, has been investigated to evaluate its convenience and suitability. Solvents of different polarity, different GC conditions and several HCl doping procedures were tested. The tendency of these organotin compounds to decompose on injection can be minimized by using strictly defined operating parameters, viz., an injector temperature of 250-300°C, an initial column temperature ≤ 80°C and a concentration of doping agent (HCl) between 0.012 and 0.08 mol l-1, for butyltin species and monophenyltin. Nevertheless, the determination of di- and triphenyltin in a sample containing both butyl- and phenyltin compounds was not possible without significant decomposition of the analytes (above 15%).