Gas Chromatographic Determination of Butyltin Compounds in Water Using Hydride Derivatization

The marine antifouling agent tributyltin and its degradation products were determined in estuarine water by in-situ hydride derivatization using aqueous sodium borohydride with simultaneous extraction into dichloromethane. The butyltin hydrides were determined using gas chromatography with tin-selective flame photometric detection. The detection limit for tributyltin in a 200-ml water sample is 5 ng l-1 (0.017 nM) by using this method. An aqueous tributyltin solution prepared by the National Institute of Technology and Standards (formerly the National Bureau of Standards) for a 35-laboratory comparison was analyzed by the new method. The result obtained by the new method is within 4% of the mean value of the determination for the 35 laboratories and within 9% of the value determined by neutron activation analysis. Fourteen marine and estuarine water samples were analyzed for di- and tributyltin in an interlaboratory exercise. For tributyltin, agreement between the new method and an existing one was within 20% for 9 of the 14 samples.