Abstrait

Utility of dispersive liquid-liquid microextraction based on ionic liquid for spectrophotometric determination of titanium in environmental samples

Alaa S Amin, Zakia Al-Malah

A novel fast and simple dispersive liquid–liquid microextraction depended on ionic liquid (IL) is applied for the first time to preconcentrate trace amount of titanium as a prior step to its spectrophotometric determination. In this procedure, least volume of an IL (1-hexyl-3- methylimmidazolium bis(trifluormethylsulfonyl)imid) as the extractive solvent was dissolved in acetonitrile as the disperser solvent and the binary solution was then injected rapidly by a syringe into the water sample containing Ti(IV) complexed using 4-(2-benzothiazolyl-azo)2,2`- biphenyldiol (BTABPD) in the presence of sodium dodecyl sulphate (SDS) as the anti-sticking agent. The cloudy solution was formed and the Ti–BTABPD complex was extracted into the fine IL droplets. The droplets of extractant were settled at the bottom of a conical test tube after centrifuging, and the extracted phase was diluted with 100 μL of ethanol and measured spectrophotometrically at 626 nm. Parameters affect the formation of the complex and its extraction, as reagent concentration, pH, salt concentration, type and concentration of antisticking agent, and the type and volumes of extraction disperser solvents, which is optimized for the presented procedure. The enhancement factor of 250 was obtained for 25 mL of water under optimum conditions. The detection limit (LOD) of the procedure was found to be 0.06 ng mL−1 and the RSD (n=5) for 2.0 ng mL−1 of Ti(IV) was 1.53%.