CONICET | Buscador de Institutos y Recursos Humanos

Mercury and its different chemical species are considered very harmful pollutants due to its high toxicity, even at low concentrations [1]. Owing to their lipophilic nature, organic Hg species are more toxic than inorganic ones. Therefore, there is a constant demand for accurate and sensitive methods for Hg speciation analysis [2].In this work, an exploration of the effects of different ionic liquids (ILs) on the separation of Hg species by RP-HPLC was performed. Imidazolium and phosphonium ILs were evaluated as mobile phase additives for the separation of Hg2+, methylmercury (CH3Hg+) and ethylmercury (C2H5Hg+) followed by their determination with RP-HPLC coupled to on-line photo-oxidation step CV-AFS. After a careful optimization, the separation of Hg species was achieved within 12 min using a C18 column and a gradient developed with a mobile phase containing 0.4% (v/v) 1-octyl-3-methylimidazolium chloride ([C8mim]Cl) at pH 2.0. In addition, a multivariate methodology was applied to optimize the parameters involved in UV-CV-AFS detection of Hg species. The limits of detection for Hg2+, CH3Hg+ and C2H5Hg+ were 110, 47 and 65 ng Hg L-1, respectively.The possible separation mechanisms could involve the formation of anionic chlorocomplexes, their ion pairing reaction with cations of ILs and the retention of the formed apolar ion pairs on the C18 stationary phase. Retention times and resolution of Hg species were highly dependent on the alkyl chain length of substituent groups of imidazolium-type ILs.The proposed method was applied for Hg speciation analysis in different canned and fresh seafoods and, as expected, it was observed that organic Hg species were predominant. Concentrations of Hg species in the canned seafood were in the ranges of

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