Ionic liquid-based dispersive liquid-liquid microextraction and enhanced spectrophotometric determination of molybdenum (VI) in water and plant leaves samples by FO-LADS

A new simple and rapid ionic liquid-based dispersive liquid-liquid microextraction (IL-DLLME) has been applied to preconcentrate trace levels of molybdenum (VI) as a prior step to its enhanced determination by fiber optic-linear array detection spectrophotometry (FO-LADS). In this method, a small amount of [Hmim][Tf2N] (1-hexyl-3-methylimmidazolium bis (trifluormethylsulfonyl) imid) as an extraction solvent was applied to extract molybdenum - pyrogallol red complex, which was formed in an aqueous solution in the presence of N-cetyl-N-N-N-trimethyl ammonium chloride as a sensitizing agent. Under optimum conditions, enhancement factor, detection limit and relative standard deviation (n = 5, for 30 μg L−1 of molybdenum (VI)) in 10 mL water sample were 72.6, 1.43 μg L−1 and 2.8%, respectively.