Improved routine speciation of organotin compounds in environmental samples by pulsed flame photometric detection

The high toxicity of the organotin species requires sensitive analytical me thods in order to understand the origins of pollution and perform monitorin g programs in the water cycle. The optimisation of a new detection method, pulsed flame photometric detection (PFPD), is reported for the simultaneous determination of butyl-, phenyl- and octyltins. The methodology of the exp erimental designs at two levels was used. It allows the evaluation of the i nfluence of the three gas flow-rates on the peak heights and resolution bet ween the closest peaks obtained using two different wavelengths of detectio n (390 and 611 nm). The modelling of these two responses, according to seco nd-order polynomials, leads to the precise adjustment of the operating cond itions. PFPD has shown two significant improvements over conventional flame photometric detection: increased sensitivity (absolute detection limits: 0 .07 to 2 pg as Sn) and greater selectivity, whatever the wavelength used. T his new analytical process was validated by the analysis of certified refer ence material and spiked river water. It was used in routine analysis of en vironmental samples (wastewater, sludge, sand and oyster). (C) 2000 Elsevie r Science B.V. All rights reserved.