Tartrazine determination from mustard sample by TLC-Photodensitometry and TLC-Digital processing of images

A facile and rapid thin-layer chromatography (TLC) method for tartrazine analysis from mustard is proposed. Silica gel precoated plates and isopropyl alcohol-ammonia mixture as mobile phase were used for tartrazine determination. The synthetic dye was extracted from solid matrix by ultrasound assisted extraction with a methanol-ammonia mixture and further purified by ion-pair solid phase extraction, using hexadecyltrimethylammonium-bromide as ion-pair reagent. Recovery determination was carried out on mustard samples spiked with tartrazine at different concentration levels. Good recoveries, around 98%, and a relative standard deviation of 17.4% were obtained. An extensive study for the quantitative evaluation of dyes was developed by comparing the photodensitometric results with those obtained by using digital processing of scanned plates with ImageDecipher-TLC software. The method was applied for the tartrazine determination in various mustard samples purchased from a local market.