Critical evaluation of fiber coatings for organotin determination by using solid phase microextraction in headspace mode.

In the present work three different SPME fibers have been investigated for simultaneous determination of methyl-, butyl- and phenyltins by using gas chromatography-pulsed flame photometer detection (GC-PFPD). The optimal experimental conditions for each fiber were determined and the respective figures of merit were evaluated. All fiber evaluated presented similar limit of detection (sub ng L⁻¹) and requires two internal standards to reach an acceptable repeatability. However, the CAR-PDMS fiber offers the best compromise between selectivity and sensibility for determination of organotins selected. The developed method was validated for analysis of certified reference material and spiked samples, obtaining satisfactory results. Finally, some contaminated samples were analyzed demonstrating the applicability of developed method for determination of organotin compounds in the environment and for monitoring their biochemical cycle.