Analysis of Tributyltin and Triphenyltin in Water by Ionic Liquid-Headspace Single-Drop Microextraction then HPLC with Fluorimetric Detection

A novel method using ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6] as extracting solvent in head-space single drop microextraction followed by HPLC with fluorimetric detection has been developed for analysis of tributyltin (TBT) and triphenyltin (TPhT) in water. Experimental conditions related to SDME performance, for example micro-drop volume, extraction time, stirring rate, salt content, and sample volume were investigated. Under the optimized conditions (micro-drop volume, 10 mu L; extraction time, 30 min; stirring rate, 900 rpm; salt concentration, 6%; sample volume, 6 mL), the linear range, detection limit (S/N = 3), and reproducibility (RSD, n = 4) were 1-100 mu g L-1, 0.62 mu g L-1, and 7.8%, respectively, for TBT, and 2-100 mu g L-1, 0.95 mu g L-1, and 8.3% for TPhT. All micro-extraction experiments were performed at room temperature (25 +/- 1 degrees C). The optimized procedure was successfully used for analysis of TBT and TPhT in deionized water and waste water. Recovery of a 25 mu g L-1 spike was in the range 86.9-92.1%. The method has also been used for analysis of TBT and TPhT in natural water.