The Determination of Pesticidal and Non-Pesticidal Organotin Compounds in Water Matrices by in situ Ethylation and Capillary Gas Chromatography -[Pulsed] Flame Photometric Detection

The concurrent determination of pesticidal and non-pesticidal organotin compounds in several water matrices, using a simultaneous in situ ethylation and liquid-liquid extraction followed by splitless injection mode capillary gas chromatography with pulsed flame photometric detection, is described. The speciation analysis of nine organotin compounds includes low molecular weight low boiling (non-pesticidal) and high molecular weight high boiling analytes (pesticidal) of significant environmental interest. The minimum time for sodium tetraethylborate alkylation, using mechanical agitation, is determined to be fifteen minutes in order to ensure the complete derivatization of the complete list of analytes. The utilization of a “hot needle” and a rapid injection rate is shown to be an efficacious means to eliminate “mass” or “needle” discrimination when determining the mixture of organotin compounds. Method detection limits are calculated to be in the low ng L range. The final method is applied to various water samples; storm water from the Cincinnati area demonstrated low native levels of three of the organotin compounds.