Simultaneous determination of red and yellow artificial food colourants and carotenoid pigments in food products.

A method for simultaneously determining four artificial food colourants [Red Nos. 2 (R2) and 40 (R40), Yellow Nos. 5 (Y5) and 6 (Y6)] and three carotenoids [lycopene, lutein, and β-carotene] was developed. They were successfully separated by the developed high pressure liquid chromatography (HPLC) method combined with a photo diode array detector. The detection limit (at signal to noise>4) was from the lowest of 0.2 ng/mL for lutein to the highest of 50.0 ng/mL for R40. With a two-phase solvent and ultrasound-assisted extraction, the recoveries of the artificial and natural pigments in fifteen different types of food products were between 80.5-97.2% and 80.1-98.4%, respectively. This HPLC method with the ultrasound-assisted extraction protocol could be used as a sensitive and reliable analysis technique in simultaneously identifying and quantifying the reddish and yellowish pigments in different foods regardless of they are artificial food colourants or/and natural carotenoids.