Simultaneous deep eutectic solvent based microextraction of Allura Red and Brilliant Blue in violet-purple foodstuffs

Abstract

A vortex-assisted simultaneous deep eutectic solvent based microextraction and spectrophotometric determination method was established for the first time to simultaneously monitor Allura Red and Brilliant Blue in violet-purple foodstuffs. A ternary deep eutectic solvent was created using benzoic acid, tetra butyl ammonium bromide and benzyl alcohol at 1:1:3mol ratio. The method variables including pH, volume of deep eutectic solvent and vortex time were optimized by Box-Behnken design of response surface methodology. The limits of detection were determined to be 25 and 9µg/L for Allura Red and Brilliant Blue, respectively. The linear dynamic ranges of the method were obtained between 82-12000 and 29-4200µg/L for Allura Red and Brilliant Blue, respectively. Preconcentration factor of the method was obtained as 15. Greenness evaluation was performed using Analytical GREEnness tools. Extraction mechanisms affecting quantitative simultaneous microextraction of the target dyes were explained. The developed method was validated with high-performance liquid chromatography analysis. Analyte addition-recovery tests were also applied to confectionery samples to validate the proposed method and determine the dye contents of foodstuffs. Allura Red and Brilliant Blue contents of violet-purple confectioneries were determined between 3.85-74.59 and 4.02-26.11µg/g concentrations with 94.5-98.6% and 93.0-101.0% recoveries, respectively.