title: Determination of inorganic selenium species in water and garlic samples with on-line ionic liquid dispersive microextraction and electrothermal atomic absorption spectrometry.
abstract: A non-chromatographic separation and preconcentration method for Se species determination based on the use of an on-line ionic liquid (IL) dispersive microextraction system coupled to electrothermal atomic absorption spectrometry (ETAAS) is proposed. Retention and separation of the IL phase was achieved with a Florisil(®)-packed microcolumn after dispersive liquid-liquid microextraction (DLLME) with tetradecyl(trihexyl)phosphonium chloride IL (CYPHOS(®) IL 101). Selenite [Se(IV)] species was selectively separated by forming Se-ammonium pyrrolidine dithiocarbamate (Se-APDC) complex followed by extraction with CYPHOS(®) IL 101. The methodology was highly selective towards Se(IV), while selenate [Se(VI)] was reduced and then indirectly determined. Several factors influencing the efficiency of the preconcentration technique, such as APDC concentration, sample volume, extractant phase volume, type of eluent, elution flow rate, etc., have been investigated in detail. The limit of detection (LOD) was 15 ng L(-1) and the relative standard deviation (RSD) for 10 replicates at 0.5 μg L(-1) Se concentration was 5.1%, calculated with peak heights. The calibration graph was linear and a correlation coefficient of 0.9993 was achieved. The method was successfully employed for Se speciation studies in garlic extracts and water samples.
authors.affiliation: Analytical Chemistry Research and Development Group (QUIANID), (LISAMEN - CCT - CONICET - Mendoza), Av. Ruiz Leal S/N Parque General San Martín, M 5502 IRA Mendoza, Argentina.
authors.forename: Estefanía M
authors.initials: EM
authors.lastname: Martinis
authors.forename: Leticia B
authors.initials: LB
authors.lastname: Escudero
authors.forename: Paula
authors.initials: P
authors.lastname: Berton
authors.forename: Romina P
authors.initials: RP
authors.lastname: Monasterio
authors.forename: María F
authors.initials: MF
authors.lastname: Filippini
authors.forename: Rodolfo G
authors.initials: RG
authors.lastname: Wuilloud
mesh_terms: D005737:Garlic / Q000737:chemistry*; D006851:Hydrochloric Acid / Q000737:chemistry; D007202:Indicators and Reagents / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry*; D059627:Liquid Phase Microextraction / Q000379:methods*; D009862:Online Systems; D009943:Organophosphorus Compounds / Q000737:chemistry; D011759:Pyrrolidines / Q000737:chemistry; D018036:Selenium Compounds / Q000032:analysis* / Q000302:isolation & purification*; D013054:Spectrophotometry, Atomic / Q000379:methods*; D013859:Thiocarbamates / Q000737:chemistry; D014867:Water / Q000737:chemistry*
chemical_list: D007202:Indicators and Reagents; D052578:Ionic Liquids; D009943:Organophosphorus Compounds; D011759:Pyrrolidines; D018036:Selenium Compounds; D013859:Thiocarbamates; C559940:trihexyltetradecylphosphonium chloride; D014867:Water; C020972:pyrrolidine dithiocarbamic acid; D006851:Hydrochloric Acid