Detection of Methyl Orange in Saffron and Other Edibles Using Direct Injection Micellar Liquid Chromatography

A simple, sensitive, rapid and eco friendly micellar liquid chromatographic method was developed for the detection of banned color methyl orange in counterfeit saffron and prepared foodstuffs. Methyl orange (p-[[p-(dimethylamino) phenyl] azo] benzenesulfonic acid sodium salt) is a hazardous dye used in titration and is known to be used as common adulterant in counterfeit saffron and cooked foodstuffs like Jalebi (Indian sweet), mango shake, Namkeen (salted snacks), tomato ketchup and ice candy etc., due to its pleasant orange color. In the present work, methyl orange was detected in various food samples using direct injection micellar liquid chromatography without any pretreatment step. A C18 column with an optimum micellar mobile phase containing 0.05-M sodium dodecyl sulfate (SDS), 2 % pentanol buffered to pH 7 was used. Detection was carried out at 458 nm. The retention time was 3.7 min without showing any matrix effect. Linearity (r > 0.9999), intraday and interday precision RSD (%) was less than 1.00 in micellar media. Limit of detection and quantification was found to be 0.05 mg/kg and 0.10 mg/kg, respectively. Robustness study was also included as a part of method validation. The developed method proved to be reliable and sensitive for determination of methyl orange in real food samples.