Vortex-assisted dispersive liquid-liquid microextraction based on hydrophobic deep eutectic solvent for the simultaneous identification of eight synthetic dyes in jellies and drinks using HPLC-PDA

Abstract

Food dye quantity as well as their permitted limit and type, is of particular importance in the food industry. Hence, it is imperative to develop alternative methods to measure them in food quality control laboratories. For the first time, deep eutectic solvents was utilized in the concurrent extraction and separation of eight common synthetic dyes of Tartrazine, Quinoline Yellow, Sunset Yellow, Brilliant Blue, Ponceau 4R, Indigo Carmine, Allura Red, and Carmoisine in jellies and drinks. The results revealed that deep eutectic solvent was prepared from benzyltriethylammonium chloride, which is a hydrogen bonding acceptor. This combination with thymol as a hydrogen bonding donor can have better efficiency in extracting the dyes than the deep eutectic solvent, such as choline chloride combined with thymol. The enrichment factor was between 18.6 and 27.2 in the eight determined dyes. The limit of detection and limit of quantitation, ranged from 0.02 to 0.05 µg L−1 and from 0.04 to 0.15 µg L−1, respectively. Within a day and between day's relative standard deviations was calculated for the two levels of concentration (10 and 100 µg L−1), which was equal to 0.9–3.3% and 2.5–7.3%, respectively. The relative recoveries for the eight synthetic dyes was for the three levels of concentration (10, 100 and 500 µg L−1), between 87.2 and 107.4% in jelly samples and 89.1 to 104% in the drink samples, which was comparable to solid phase extraction method. As a result, the deep eutectic solvents -based dispersive liquid–liquid microextraction method can be announced as a powerful, fast, sensitive and easy method to measure dyes in jellies and drinks.