Separation and determination of Selenium species in food and beverages by ionic liquid-assisted reversed-phase liquid chromatography.

ALEXANDER CASTRO GRIJALBA; EMILIANO FIORENTINI; RODOLFO G. WUILLOUD

Santos, Sao Paulo

Congreso; 5th Iberoamerican Meeting on Ionic Liquids (IMIL 2017); 2017

Different ionic liquids (ILs) were assayed as mobile phase modifiers for the separation and determinationof selenite [Se(IV)], selenate [Se(VI)], selenomethionine (SeMet) and Se-methylselenocysteine (SeMeSe-Cys) by reversed-phase high-performance liquid chromatography coupled to hydride generation atomicfluorescence spectrometry (RP-HPLC-HG-AFS). The use of several ILs: 1-butyl-3-methylimidazoliumchloride, 1-hexyl-3-methylimidazolium chloride ([C6mim]Cl), 1-octyl-3-methylimidazolium chloride,1-dodecyl-3-methylimidazolium bromide, 1-hexadecyl-3-methylimidazolium bromide and trib-utyl(methyl)phosphonium methylsulphate was evaluated. Also, the effect of pH, buffer type and ILconcentration on the separation of Se species was studied. Complete separation was attained within12 min using a C8column and a gradient performed with a mobile phase containing 0.1% (v/v) [C6mim]Clat pH 6.0. The proposed method allows the separation of inorganic and organic Se species in a single chro-matographic run, adding further benefits over already reported methods based on RP-HPLC. In addition,the influence of ILs on the AFS signals of each Se species was evaluated and a multivariate methodologywas used for optimization of AFS sensitivity. The limits of detection were 0.92, 0.86, 1.41 and 1.19 g L−1for Se(IV), Se(VI), SeMet and SeMeSeCys, respectively. The method was successfully applied for speciationanalysis of Se in complex samples, such as wine, beer, yeast and garlic.