Temperature-induced aggregation ionic liquid dispersive liquid-liquid microextraction method for separation trace amount of cobalt ion

A simple and rapid temperature induced aggregation micro extraction method based on ionic liquid for extraction and preconcentration of cobalt ions from water samples was proposed. In this investigation small amounts of 1-hexyl-3-methylimidazolium hexafluorophosphate [Hmim][PF6] and 1-hexyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)imide [Hmim][Tf2N] (as extractant solvents) were added in a sample solution containing Triton X-114 (as an anti-sticking agent). After centrifuging the cooled solution, analysis was carried out by flame atomic absorption spectrophotometry. Some effective parameters have been optimized. Under the optimum conditions, detection limit of the method was 0.44 ng/mL and the relative standard deviation (RSD) for 100.0 ng/mL cobalt was +/- 2.3% (n = 7).The calibration curve was linear in the range of 3.0-200.0 ng/mL cobalt and enrichment factor was obtained as 26.5. The applicability of the technique was evaluated by the determination of trace amounts of cobalt in several water samples and synthetic alloys.