New approach of solid-phase microextraction improving the extraction yield of butyl and phenyltin compounds by combining the effects of pressure and type of agitation.

A new methodology for the simultaneous and fast solid-phase microextraction (SPME) of butyl- and phenyltin compounds, as ethylated derivates, is proposed in this paper. The effects of pressure and type of agitation during headspace SPME sampling are evaluated and discussed on the basis of thermodynamic considerations. Quantitative structure-activity relationships were used to estimate analytes partition coefficients allowing to explain the different behaviours experimentally observed. SPME sampling conditions including mechanical stirring and reduced pressure result in simultaneous higher efficiency (detection limits especially lowered for phenyltins up to a eight-fold reduction) and shorter sampling time (two-fold reduction).