Microextraction and preconcentration technique based on magnetic ionic liquid for the determination of chrome by electrothermal atomic absorption spectrometry applied to honey sample

EMILIANO F. FIORENTINI; MARIA N. OVIEDO; RODOLFO G. WUILLOUD

Mendoza

Simposio; 15th Rio Symposium on Atomic Spectrometry; 2019

LABORATORIO DE QUIMICA ANALITICA PARA INVESTIGACION Y DESARROLLO ; FACULTAD DE CIENCIAS EXACTAS Y NATURALES ; UNIVERSIDAD NACIONAL DE CUYO

In the present work, a novel LLME technique based on the formation of ion pairs between the MIL trihexyl(tetradecyl)phosphonium tetrachloroferrate ([P6,6,6,14]FeCl4) and the anion [Cr(H2O)2Cl4]- was developed for the preconcentration and determination of Cr by electrothermal atomic absorption spectrometry (ETAAS). The resulting method consisted in adjusting the acidity of samples to a concentration of 1 mol L -1 HCl, followed by the extraction of Cr with the MIL, the use of acetonitrile as a dispersant and vortexing. The MIL was collected with the use of a magnetic rod, diluted in CHCl3 and an aliquot of the eluate was injected into the graphite furnace of ETAAS for Cr determination. Under optimal experimental conditions, an extraction efficiency of 95% was obtained, an LOD of 41 ng L -1 of Cr and a relative standard deviation (RSD) of 3.2% (for a Cr solution of 1 µgL -1 and n=10). The proposed methodology was successfully applied to honey samples previously treated in muffle oven and diluted.