Ionic liquid-assisted separation and determination of selenium species in food and beverage samples by liquid chromatography coupled to hydride generation atomic fluorescence spectrometry

ALEXANDER CASTRO GRIJALBA; EMILIANO FIORENTINI; RODOLFO G. WUILLOUD

JOURNAL OF CHROMATOGRAPHY - A

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017

0021-9673

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 tributyl(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 C8 column 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 chromatographicrun, 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.