Dispersive liquid-liquid microextraction based on task-specific ionic liquids for determination and speciation of chromium in human blood

In this study, a simple dispersive liquid-liquid microextraction method based on task-specific ionic liquids was applied for highly sensitive determination and speciation of chromium (III, VI) in human blood by electro-thermal atomic absorption spectrometry. In this method, a mixture containing of 1-(3-aminopropyl)-3-methylimidazolium hexafluorophosphate [APMIM][PF6] and 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4] (extracting solvent), acetone (dispersant) and TX-100 (anti-sticking agent) were added to Cr(VI) solution in 1 mL blood samples that was extracted by binary mix ionic liquids. For extraction of Cr(VI) anions, the binary mix ionic liquids ([APMIM][PF6], [BMIM][BF4]) and acetone were used as extracting and dispersant solvent, respectively. Total chromium was simply obtained by oxidation of Cr(III) to Cr(VI) by H2O2 solution, and Cr(III) is calculated by difference between total chromium and Cr(VI). Under the optimal conditions, the calibration graph and limit of detection were 0.02–0.9 µg/L and 5 ng/L, respectively. The developed method was applied successfully to determination and speciation Cr (III, VI) in human blood samples.