Inorganic selenium speciation analysis in Allium and Brassica vegetables by ionic liquid assisted liquid-liquid microextraction with multivariate optimization. (15th March 2017)

• Record Type: Journal Article
• Authors: Castro Grijalba, Alexander; Martinis, Estefanía M.; Wuilloud, Rodolfo G.
• Is Part Of: Food chemistry. Volume 219(2017)
• Page Start: 102
• Page End: 108
• Publication Date: 2017-03-15
• Subjects: Selenium -- Phosphonium ionic liquid -- Liquid-liquid microextraction -- Allium -- Brassica; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2016.09.117
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Non-chromatographic speciation of inorganic Se and preconcentration by VA-IL-LLME. Efficient sample clean-up and elimination of organic interferences using MWCNTs. Multivariate optimization reduced the number of experiments needed in VA-IL-LLME. Highly sensitive determination of Se species in Allium and Brassica plants. 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 5.0 ng/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.