title: Inorganic selenium speciation analysis in Allium and Brassica vegetables by ionic liquid assisted liquid-liquid microextraction with multivariate optimization.
abstract: A highly sensitive vortex assisted liquid-liquid microextraction (VA-LLME) method was developed for inorganic Se [Se(IV) and Se(VI)] speciation analysis in Allium and Brassica vegetables. Trihexyl(tetradecyl)phosphonium decanoate phosphonium ionic liquid (IL) was applied for the extraction of Se(IV)-ammonium pyrrolidine dithiocarbamate (APDC) complex followed by Se determination with electrothermal atomic absorption spectrometry. A complete optimization of the graphite furnace temperature program was developed for accurate determination of Se in the IL-enriched extracts and multivariate statistical optimization was performed to define the conditions for the highest extraction efficiency. Significant factors of IL-VA-LLME method were sample volume, extraction pH, extraction time and APDC concentration. High extraction efficiency (90%), a 100-fold preconcentration factor and a detection limit of 5.0ng/L were achieved. The high sensitivity obtained with preconcentration and the non-chromatographic separation of inorganic Se species in complex matrix samples such as garlic, onion, leek, broccoli and cauliflower, are the main advantages of IL-VA-LLME.
authors.affiliation: Laboratory of Analytical Chemistry for Research and Development (QUIANID), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Padre J. Contreras 1300, 5500 Mendoza, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
authors.forename: Alexander
authors.initials: A
authors.lastname: Castro Grijalba
authors.affiliation: Laboratory of Analytical Chemistry for Research and Development (QUIANID), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Padre J. Contreras 1300, 5500 Mendoza, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
authors.forename: Estefanía M
authors.initials: EM
authors.lastname: Martinis
authors.affiliation: Laboratory of Analytical Chemistry for Research and Development (QUIANID), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Padre J. Contreras 1300, 5500 Mendoza, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina. Electronic address: rodolfowuilloud@gmail.com.
authors.forename: Rodolfo G
authors.initials: RG
authors.lastname: Wuilloud
mesh_terms: D001937:Brassica / Q000737:chemistry*; D005737:Garlic / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods*; D011759:Pyrrolidines / Q000032:analysis; D012643:Selenium / Q000032:analysis*; D018036:Selenium Compounds / Q000032:analysis*; D013054:Spectrophotometry, Atomic / Q000379:methods; D013859:Thiocarbamates / Q000032:analysis
chemical_list: D052578:Ionic Liquids; D011759:Pyrrolidines; D018036:Selenium Compounds; D013859:Thiocarbamates; C020972:pyrrolidine dithiocarbamic acid; D012643:Selenium
keywords: Allium; Brassica; Liquid-liquid microextraction; Phosphonium ionic liquid; Selenium