Room temperature ionic liquid-based microextraction for vanadium species separation and determination in water samples by electrothermal atomic absorption spectrometry

BERTON, P.; MARTINIS, E.M.,; MARTINEZ, L.D.; WUILLOUD, R.G.

ANALYTICA CHIMICA ACTA

Elsevier

Año: 2009 p. 40 - 46

0003-2670

A simple microextraction technique based on room temperature ionic liquids (RTILs) for trace V(IV) andV(V) species separation and preconcentration in water samples was developed in this work. Vanadiumspecies microextraction was achieved with a minimal amount of the RTIL 1-butyl-3-methylimidazoliumhexafluorophosphate ([C4mim][PF6]) as vanadium-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (V-5-Br-PADAP) complex. The speciation analysis was performed based on a modern technique defined astemperature-controlled ionic liquid dispersive liquid phase microextraction (TILDLME). The level of V(IV)species was calculated by difference of total V and V(V) levels. Selectivity among V species was obtainedwith the use of 1,2-cyclohexanediaminetetraacetic acid (CDTA) as masking agent. Determination of Vwasdeveloped by direct injection of the RTIL phase into the electrothermal atomic absorption spectrometer(ETAAS). A preconcentration factor of 40 was achieved with only 2mL of sample. The limit of detection(LOD) obtained under optimum conditionswas 4.9 ng L−1 and the relative standard deviation for 10 replicatedeterminations at the 0.5gL−1 V levelwas 4.3%, calculated at peak heights. A correlation coefficientof 0.9961 was achieved. The method was successfully applied for the speciation analysis of V in tap andriver water samples.