Ultrasound-assisted ionic liquid-based dispersive liquid–liquid microextraction for preconcentration of patent blue V and its determination in food samples by UV–visible spectrophotometry

Ultrasound-assisted ionic liquid-based dispersive liquid–liquid microextraction procedure (UA-IL-DLLME) was developed for determination of trace levels of patent blue V prior to its determination by UV–visible spectrophotometry. Patent blue V was extracted from 25-mL sample into a 100-μL volume of ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), with the aid of sonication in an ultrasonic bath. Several variables affecting microextraction efficiency were optimized. Under the optimum experimental conditions, the detection limit (3 s) was 0.68 μg L⁻¹, and the preconcentration factor was 100. The relative standard deviation for six replicate determinations of patent blue V was 4.5 %. The method was applied to the determination of patent blue V in food samples. The proposed procedure is effective, very simple, and fast.