Solid-phase extraction and spectrophotometric determination of Allura Red (E129) in foodstuff, soft drink, syrup and energy drink samples: a comparison study

Amberlite XAD-7 and XAD-8 resins were used as adsorbents for preconcentration and determination of Allura Red (AR) food dye in aqueous medium. The effects of pH, sample volume, sample and eluent flow rates on the extraction of AR were optimised. The determination of dye was performed at 506.0nm using spectrophotometry. Interference effects of matrix ions and some dyes were also investigated under optimised conditions. The methods permitted low detection limits which were 1.2 and 0.6gL(-1) for XAD-7 and XAD-8, respectively. Adsorption behaviours were investigated by adsorption isotherms and zero charge pH experiments. Validations of the method were performed by determination of AR contents in some foodstuffs. AR contents of liquid samples were found between 58 and 440gmL(-1). AR concentrations of solid samples were between 416 and 432gg(-1). The XAD-7 and XAD-8 resins presented a fast and reliable potential to determine AR dye in real samples.