Ultrasound-assisted ionic liquid based dispersive liquid-liquid microextraction and flame atomic absorption spectrometry of cobalt, copper, and zinc in environmental water samples

In the present study, the simultaneous preconcentration of copper, cobalt and zinc based on ultrasound-assisted ionic liquid-based dispersive liquid-liquid microextraction as a prior step to their determination by flame atomic absorption spectrometry was developed. Some effective parameters such as type and volume of extraction and dispersive solvents, concentration of complexing agent, pH of sample solution, salting out effect, and sonication time were studied and optimized. Under the optimal conditions (including extraction solvent: 1-hexyl-3-methylimidazolium hexafluorophosphate [HMIM][PF6]], 90 mg; dispersive solvent: acetone, 220 mu L; complexing agent: N,N'-bis(2-salicylaldiminato)-1,8-diamino-3,6-dioxaoctane, 4.0 x 10(-2) mol L-1; pH of sample: 6.5; without salt addition; and sonication time: 2 min), limits of detection (LODs), linear ranges (LRs), preconcentration factor (PF), enhancement factor (EF) and consumptive index (Cl) were ranging from 1.9 to 4.4 mu g L-1, 6 to 500 mu g L-1, 50,48 to 56, and 0.18 to 0.21 for these ions in the real samples, respectively. The suggested procedure was successfully applied for the determination of the copper, cobalt and zinc ions in environmental water samples. (C) 2014 Elsevier B.V. All rights reserved.