Speciation of butyl and phenyltin compounds using dispersive liquid–liquid microextraction and gas chromatography-flame photometric detection

Dispersive liquid–liquid microextraction and gas chromatography-flame photometric detection (DLLME-GC-FPD) were performed for the speciation of butyl and phenyltin compounds in water samples after derivatization with sodium tetraethylborate (NaBEt4). Some important parameters, such as pH, amount of NaBEt4, derivatization time, kind and volume of extraction and disperser solvents, extraction time and salt effect were investigated and optimized. High enrichment factors (825–1036) and low detection limits (0.2–1 ng L−1) were obtained under the optimum conditions. The calibration graphs were linear in the range of 0.5–1000 ng L−1 (as Sn) for the target analytes. The relative standard deviations (RSDs) for the extraction of 20 ng L−1 (as Sn) of butyl and phenyltin compounds varied from 2.3 to 5.9% (n = 7) and from 4.1 to 8.8% (n = 7) with and without using internal standard, respectively. Seawater and river water samples were successfully analyzed using the proposed method and the relative recoveries of the studied compounds in the water samples, at spiking levels of 10.0 and 100 ng L−1 (as Sn) were obtained to be 82.5–104.7%.