Simultaneous deep eutectic solvent based microextraction for monitoring Brilliant blue and rhodamine B in foodstuff and industrial samples

Brilliant blue (Bb) (legal food dye) and rhodamine b (Rb) (illegal food dye) are artificial dyes used in different industries such as food and cosmetic. Due to their toxic effects on humans, extreme exposure to these food additives can lead to health problems. Simultaneous deep eutectic solvent based (DES) microextraction method was developed first time for spectrophotometric determination of Bb and Rb. DES composed of 1-heptanol and tetra butyl ammonium bromide (TBAB) was synthesized and then used for simultaneous microextraction of Bb and Rb. Effects of pH, composition ratio and volume of DES, time of vortex mixing, centrifugation time and rate, sample volume and matrix components were investigated to achieve quantitative simultaneous microextraction of the dyes. The detection limits 20 and 13 µg/L, linear dynamic ranges between 0.068–4.5 and 0.042–3 µg/mL and 40 preconcentration factors were obtained for Bb and Rb, respectively. Bb and Rb contents of commercially available industrial samples were determined between 3.85–6.28 µg/mL and 1.05–23.50 µg/g for liquid and solid samples, respectively. Quantitative recoveries ranging from 92 to 106% were obtained in multivariable analyte addition-recovery tests. In addition to dye content determination process of real samples and method development studies, extraction mechanisms of method were elucidated for Bb and Rb. Green Analytical Procedure Index (GAPI) and score of Analytical Eco-Scale (AES) were evaluated. [Display omitted] •Determination of Brilliant blue (Bb) and Rhodamine B (Rb) in industrial samples.•Monitoring legal Bb and illegal Rb food dyes in various food matrices.•Application of worthy green method for microextraction of Bb and Rb.•Simultaneous UV–vis spectrophotometric determination of Bb and Rb.•The electro-neutral structures of Bb and Rb were extracted at pH 5.