Abstract:

Dispersive liquid-liquid microextraction (DLLME) has become a very popular environmentally benign sample preparation technique, due to its simplicity, speed of operation and low consumption of solvent and reagent. It has attracted much interest from scientists working in separation science, and much improvement has been made since its introduction in 2006. This work reports the development of a new simple ionic liquid based dispersive liquid-liquid microextraction (IL-DLLME) method for spectrophotometric copper determination. First, the copper was complexed with a novel silicone phthalocyanine and than the complex was extracted into 1-heptyl-3-methylimidazolium hexafluorophosphate dissolving in acetone in the presence of sodium dodecyl sulphate (SDS) as the anti-sticking agent. After centrifuging for 2 min at 3000 rpm, the extracting phase was diluted to 250 µL with acetone for spectrophtometric detection at 340 nm. Some experimental conditions that influence the procedure were optimized. The pH and complexing reagent concentration are 4.0 and 4.6x10-6 molL-1, respectively. The method is linear in the range from 0.03 to 100 µg/mL with a correlation coefficient (R2) of 0.9973. The limit of detection (LOD) of method is 0.017 µg/mL. The relative standard deviation is 1.7% at 45 µg/mL Cu2+ (n=6).  The enrichment factor for the method was calculated as 210.

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