Reagent sequence for planar chromatographic analysis of eight sweeteners in food products approved in the European Union

Abstract

AbstractSweeteners, which are regulated as food additives in the European Union, are used as tabletop sweeteners or added to foods for sweetening with the aim of reducing the calorie content. For their simple analysis, a quantitative high-performance thin-layer chromatography multi-imaging (HPTLC−UV/Vis/FLD) method was developed, which used a reagent sequence to detect eight important sweeteners in eight different food products. The samples were dissolved or diluted and separated on HPTLC plates silica gel 60 F254 with a mixture of ethyl acetate, methanol, and acetic acid 5:1:1, V/V. Due to the different structures and detectabilities of the sweeteners, different post-chromatographic derivatization reagents were compared for multi-detection of the sweeteners on the same plate. First, the UV absorbance was detected, and then the derivatization reagent sequence was performed with the primuline reagent, then ninhydrin glacial acetic acid reagent, and finally 2-naphthol sulfuric acid reagent. It was important to arrange and use the reagents according to their increasing acidity. Zones of interest can be confirmed by mass spectrometry. Compared to the status quo analysis of sweeteners, the whole method is simple, robust, and rapid considering the minimalist sample preparation and reagent sequence applied on the same plate. In addition, the influence of food sample matrix on the results is easily understood due to the image-giving nature and multi-detection.