A Miniaturized Gas-Liquid Separator for Use in Liquid-Phase Microextraction Procedures: Determination of Mercury in Food

A method for the preconcentration of mercury using vortex-assisted temperature-controlled dispersive liquid-phase microextraction (VA-TC-DLPME) is proposed. A miniaturized gas-liquid separator (m-GLS) was developed and applied to the determination of mercury after VA-TC-DLPME. The detection was performed using cold vapor atomic absorption spectrometry (CV AAS). Ammonium pyrrolidine dithiocarbamate (APDC) reagent was used as a complexing agent for Hg(II). The VA-TC-DLPME method consists in dispersing the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]) in the aqueous phase by vigorous vortexing, followed by heating and cooling in an ice bath. The mixture was submitted to centrifugation, and the sedimented rich phase was then dissolved in an acid solution to reduce viscosity. Mercury was quantified in the final solution using m-GLS and CV AAS. Under optimized conditions, the method presents a limit of detection of 4.5x10(-2) mu g L-1, and an enrichment factor of 54. The accuracy was evaluated by the determination of mercury in reference material-certified ERM-CE 278, mussel tissue. The method was applied to the determination of mercury in fish oil samples. The developed m-GLS can be tested for use after other LPME procedures.