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The Determination of Pesticidal and Non-Pesticidal Organotin Compounds in Water Matrices by in situ Ethylation and Gas Chromatography with Pulsed Flame Photometric Detection
Citation:
EVANS, O. M., P. KAUFFMAN, A. M. PAWLECKI-VONDERHEIDE, L. J. WYMER, AND J. N. MORGAN. The Determination of Pesticidal and Non-Pesticidal Organotin Compounds in Water Matrices by in situ Ethylation and Gas Chromatography with Pulsed Flame Photometric Detection. Microchemical Journal. Elsevier BV, AMSTERDAM, Netherlands, 92(2):155-164, (2009).
Impact/Purpose:
The goal of this research effort is development of analytical methods for the determination of compounds selected for the 1998 Contaminant Candidate List (CCL) [Note: chemicals on the CCL are denoted below with a single asterisk, *. Chemicals with a double asterisk, **, are used as Internal Standards (Recovery and Quantitative).]. These may include selected non-pesticidal* , pesticidal, and other types of organotin compounds: monomethyltin trichloride*, dimethlytin dichloride*, trimethyltin trichloride, monobutyltin trichloride*, dibutyltin dichloride*, tributyltin chloride, phenyltin trichloride, diphenyltin dichloride, triphenyltin chloride, tricyclohexyltin, tripropyltin chloride**, tetrapentyltin**, tetrabutyltin**, etc.. The method(s) should be adequate for gathering occurrence data under the Unregulated Contaminant Monitoring Rule (UCMR) and should be applicable to / for compliance monitoring in the event selected non-pesticidal and / or pesticidal organotins become regulated contaminants under the Safe Drinking Water Act (SDWA).
Description:
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-1 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.