Analytical advances in butyl-, phenyl- and octyltin speciation analysis in soil by GC-PFPD

The development and validation of a method for organotin analysis in soils, including butyl-, phenyl- and octyl-tins, are described in this study. The influence of pretreatment step based on sample lyophilization was first studied. Different solid-liquid extraction techniques including mechanical stirring (MSAE), accelerated solvent (ASE), microwave (MAE) and ultrasound (UAE), were compared. MSAE gave the best recoveries and repeatability and was thus chosen for OTC extraction from soils. Then, ethylation/extraction step before GC-PFPD analysis was investigated and the best derivatisation conditions were assessed in order to achieve a simple, non-expensive and reliable routine procedure. Finally, the robustness of the method was tested by the analysis of several soils with different organic matter content allowing the validation of developed protocol. The method appears to be reliable and accurate for the OTC determination in a broad range of soils.