Liquid-liquid microextraction based on a dispersion of Pd nanoparticles combined with ETAAS for sensitive Hg determination in water samples

A novel and highly efficient microextraction methodology based on the use of palladium nanoparticles (Pd NPs) was developed for the preconcentration and determination of Hg in water samples. Selective separation of the analyte was achieved by application of dodecanethiolate-coated Pd monolayer-protected clusters (C12S Pd MPCs) in a liquid-liquid microextraction technique (LLME). A volume of 20 mu L of toluene phase containing C12S Pd MPCs was used for extraction and final phase was injected in an electrothermal atomic absorption spectrometer (ETAAS) for Hg detection. The effects of different variables, such as sample volume, extraction time, and NPs dispersion volume were carefully studied. A sensitivity enchancement factor of 95 was obtained under optimal experimental conditions. Furthermore, low detection limit (7.5 ng L-1) and good precision (relative standard deviation of 4.1% at 0.25 mu g L-1 Hg and n = 10) were achieved. The proposed method can be considered as a rapid, cost-effective, and efficient alternative for Hg determination in water samples like river, lake, mineral and tap water. (c) 2013 Elsevier B.V. All rights reserved.