Speciation analysis of organotin compounds in human urine by headspace solid-phase micro-extraction and gas chromatography with pulsed flame photometric detection.

A new headspace solid-phase micro-extraction (HS-SPME) method followed by gas chromatography with pulsed flame photometric detection (GC-PFPD) analysis has been developed for the simultaneous determination of 11 organotin compounds, including methyl-, butyl-, phenyl- and octyltin derivates, in human urine. The methodology has been validated by the analysis of urine samples fortified with all analytes at different concentration levels, and recovery rates above 87% and relative precisions between 2% and 7% were obtained. Additionally, an experimental-design approach has been used to model the storage stability of organotin compounds in human urine, demonstrating that organotins are highly degraded in this medium, although their stability is satisfactory during the first 4 days of storage at 4 °C and pH=4. Finally, this methodology was applied to urine samples collected from harbor workers exposed to antifouling paints; methyl- and butyltins were detected, confirming human exposure in this type of work environment.

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.