Determination of Brilliant Blue FCF in food and cosmetic samples by ionic liquid independent disperse liquid–liquid micro-extraction

Abstract

A novel, relatively fast and simple method of ionic liquid independent disperse liquid–liquid micro-extraction (IL-IDLLME) coupled with UV-Visible spectroscopy was developed and applied to determination of the synthetic dye Brilliant Blue FCF (E133) in six different kinds of food and cosmetic samples, namely soft drinks, candy, jelly, kiwi fruit (Actinidia chinensis) pieces, roasted pea, ice cream, eau de toilette and shampoo. The samples were dissolved in water and preconcentrated simply by using 1-decyl-3-methylimidazolium tetrafluoroborate ([C₁₀MIM][BF₄]) without a dispersive solvent, heat, ultrasonication or additional chemical reagents. The effects of different parameters such as the volume of [C₁₀MIM][BF₄], pH, KCl concentration, micro-extraction temperature, incubation time and centrifugation time on the micro-extraction of E133 (0.12 μg mL⁻¹) were investigated and optimum conditions were established. A linear calibration curve was obtained in the range of 1.5–150 μg L⁻¹ for E133 under optimum conditions. The limit of detection (LOD) based on 3Sb was 0.34 μg L⁻¹ (n = 11). The relative standard deviation (R.S.D.) for 5 and 140 μg L⁻¹ of E133 was 0.43% and 0.82% (n = 10), respectively. The method is therefore recommended for use by the quality control departments of food and cosmetic producers using E133.