A Rapid and Green Limit Test Method for Five Synthetic Colorants in Foods Using Polyamide Thin-layer Chromatography

摘要: Synthetic food colorants are used in very small amounts. Typically, the extracted, purified and concentrated prior to analysis; however, sample preparation is time-consuming, of high cost environmentally unfriendly. In this work, a polyamide thin-layer chromatographic (TLC) method combination with on-plate solid-phase extraction backlight-assisted detection has been developed for five commonly synthetic foods. Beverages (degassed where appropriate) were directly applied TLC plate. Gelatinous solid samples first extracted water–ammonia aqueous solution (25 %) (99:1) assisted by ultrasonic treatment. Sample solutions then acidified before application. Relatively large volumes (5–25 μl) could be plate without significant diffusion. Before development, start spots cleaned up using ethanol (95 %)–water–acetic acid (5:5:0.1). The was mobile phase (95 %)–water–ammonia (75:14:1). After viewed backlight mode an LED array light. selectivity proved acceptable. limits Ponceau 4R, Amaranth, Tartrazine, Sunset Yellow Brilliant Blue 10.1, 9.59, 4.19, 4.12 2.06 ng, respectively. rapid, low-cost sensitive, providing green limit test