Vortex-assisted sequential liquid-phase micro-extraction of E127 and E129 in foodstuffs and pharmaceuticals

Abstract

In the present study, sequential liquid-phase micro-extraction (LPME) method based on amphiphile (1-pentanol) and ion-pair agent as the green chemicals for micro-separation, preconcentration and UV–vis micro-spectrophotometric determination of Erythrosine (E127) and Allura red (E129) in foodstuffs and pharmaceuticals was developed for the first time. 1-pentanol was used as extraction solvent for micro-extraction of E127 and to prepare alkanol based ion-pair solvent with tetra-pentyl ammonium bromide for micro-extraction of E129. E127 and E129 were determined by spectrophotometer at 538 and 506 nm, respectively. Micro-separation and micro-extraction parameters of the methods including pH, type and volume of 1-pentanol and ion-pair solvent, time of vortex and centrifugation were examined in detail and optimized. At the optimum conditions, interference effects of matrix components and effect of sample volume on the micro-extraction methods were investigated. Limit of detection and limit of quantification were found as 3.2 µg/L, 8.4 µg/L for E127 and 5.2 µg/L, 13.7 µg/L for E129, respectively. 15 preconcentration factor was attained for each of the dyes. The possible extraction mechanisms of the alkanol based micro-extraction for E127 and ion-pair agent based micro-extraction for E129 were elucidated in detail and also showed with images. Finally, the proposed sequential micro-separation technique was validated by analyte addition and recovery studies and applied to determine E127 and E129 contents of commercially available foodstuffs and pharmaceuticals in Turkish markets and pharmacies.