(a) HPLC profile of the two common A. vera juice preservatives: potassium sorbate and sodium benzoate. A 1 : 1 (w/w) mixture containing standard sodium benzoate and potassium sorbate was run using an ammonium acetic buffer in isocratic condition. The top and lower panels were detection at 225 and 250 nm optimised for benzoate (retention time (RT)—8.3 min) and sorbate (RT—10.1 min), respectively
(b) HPLC profile of Aloe vera products showing additives. The chromatogram was obtained under an isocratic condition (see Figure 4(a)). Ascorbic acid, sodium benzoate, and potassium sorbate are shown at retention time of 2.0, 8.3, and 10.1 min, respectively. For each sample, a pair of spectra were obtained with UV detection at 225 (lower panel) and 250 nm (upper panel)
Figure 4