Solid phase microextraction coupled to liquid chromatography-inductively coupled plasma mass spectrometry for the speciation of organotin compounds in water samples

Abstract

Solid-phase microextraction (SPME) coupled to high performance liquid chromatography (HPLC) and the subsequent detection by inductively coupled plasma-mass spectrometry (ICP-MS) was used as a new approach for the determination of tributyltin (TBT), triphenyltin (TPhT), trimethyltin (TMeT) and tripropyltin (TPrT) in water samples. These organometallic compounds were extracted on a coated fiber and desorbed in static mode in a SPME/HPLC interface. Triorganotin compounds were separated using a mobile phase of water–acetonitrile–acetic acid (50 : 40 : 10) at a flow-rate of 0.3 mL min⁻¹. In order to reduce the solvent loading on the plasma, the spray chamber was cooled to −5 °C and oxygen (0.1 L min⁻¹) was mixed into the make-up gas by a mass-flow controller. The extraction and preconcentration capabilities of SPME and the monitorization of ¹²⁰Sn isotope signal by ICP-MS during the run provided detection limits ranging between 6 and 185 ng L⁻¹Sn as well as good repeatability (inter-day RSD < 19.23%). This method was applied to the determination of triorganotins in freshwaters and seawater of leisure ports, which demonstrates the usefulness of this technique for organotins.