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

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 pharmaceuti-cals 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, inter-ference 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 mu g/L, 8.4 mu g/L for E127 and 5.2 mu g/ L, 13.7 mu g/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.

Automated summary

In this study, a sequential liquid-phase micro-extraction (LPME) method using 1-pentanol and ion-pair agent was developed for the separation and determination of Erythrosine (E127) and Allura red (E129) in foodstuffs and pharmaceuticals. The methods involved micro-extraction using 1-pentanol for E127 and an alkanol-based ion-pair solvent with tetra-pentyl ammonium bromide for E129. The parameters of the methods were optimized, and the extraction mechanisms were elucidated. The proposed technique was validated and applied to commercially available samples in Turkish markets and pharmacies.