INVESTIGADORES
WUILLOUD Rodolfo German
congresos y reuniones científicas
Título:
Preconcentration and separation of selenium species by ionic liquid based on-line liquid-liquid microextraction prior to electrothermal atomic absorption spectrometry
Autor/es:
MARTINIS, ESTEFANIA M.; BERTON, PAULA; WUILLOUD, RODOLFO G.
Lugar:
Mar del Plata
Reunión:
Simposio; ELEVENTH RIO SYMPOSIUM ON ATOMIC SPECTROMETRY; 2010
Institución organizadora:
Comision Nacional de Energía Atómica; Universidad de Buenos Aires
Resumen:
Ionic Liquids (ILs) are generally considered to be environmentally friendlier than common organic solvents and have unique characteristics (e.g. no effective vapor pressure, adjustable viscosity and miscibility in aqueous phases). Moreover, they are also considered as highly efficient extractant phases to improve analyte selectivity and sensitivity, turning them into important tools for spectrometric analysis. Considerable interest has been appeared recently on liquid-liquid microextraction (LLME) involving ILs due to their high extraction capacity. However, microextraction methodologies based on ILs have been mostly performed in batch mode. Consequently, the risk of contamination is high and the operation is usually time-consuming. In this work, on-line IL microextraction and separation procedures are proposed for selenium species determination. After analyte extraction into tetradecyl(trihexyl)phosphonium chloride IL, on-line retention and separation of the IL enriched phase was achieved with a packed microcolumn. Selective extraction of inorganic Se(IV) species was obtained by chelation with ammonium pyrrolidine dithiocarbamate reagent while total inorganic Se was determined by a similar approach with previous reduction of Se(VI) species. Furthermore, total content of organic Se species was also assayed. Several factors influencing microextraction, separation and preconcentration efficiency of Se were investigated in detail. The method was successfully applied to inorganic Se species and total organic Se species determination in garlic and water samples by electrothermal atomic absorption spectrometry (ETAAS). P. Sun and D. W. Armstrong, Anal. Chim. Acta, 661 (2010) 1-16. E. Aguilera-Herrador, R. Lucena, S. Cárdenas and M. Valcárcel, TrAC - Trends in Anal. Chem., in Press. A. Sarafraz-Yazdi and A. Amiri, TrAC - Trends in Anal. Chem., 29 (2010) 1-14. M. N. Matos Reyes, M. L. Cervera and M. De La Guardia, Anal. Bioanal. Chem., 394 (2009) 1557-1562.