A REVERSE-PHASE HPLC METHOD TO DETERMINE 6 FOOD DYES USING BUFFERED MOBILE-PHASE

A reverse phase high performance liquid chromatographic (HPLC) method to determine six food dyes (Sunset Yellow (E-110), Carminic acid (E-12 0) Carmoisine (E-122), Amaranth (E-123), Ponceau 4R (E-124) and Erythr osine (E-127) is developed in this paper. The separation was made on a Nova-Pack C18 column using methanol -NaH2PO4/Na2HPO4 pH = 7 buffer so lution 0.1M as mobile phase with an elution gradient system. The detec tion was made with a variable UV-Vis. detector fixed at 520 mm. The ef fect of mobile phase composition such as the percentage of methanol or acetonitrile, pH value and ionic strength on retention times of the d yes was investigated. In the chromatographic conditions selected, the dyes were eluted in minutes. Two calibration graphs for each dye were established by measuring the peak area and the peak height in the chro matograms. Determination limits ranging from 0.8 to 9.2 ng were obtain ed when the peak area was measured. Several commercial products contai ning some of these dyes were analyzed.