HPLC investigation of the degradation of some artificial azo food colorants in the presence of ascorbic acid

摘要

The influence of the concentration of ascorbic acid on some azo food colorant (Brilliant Black BN, Brilliant Blue FCF, Chinoline Yellow, Indigotine, Patent Blue V and Tartazine) degradation in the solution has been studied. Rate constant (k), time of colorant half-life (t1/2), as well as the type of the kinetic reaction have been determined. The colorants and the ascorbic acid have been determined by high performance liquid chromatography (HPLC) with diode array detector (DAD) and UV-VIS spectrometry. It was found that the higher concentration of ascorbic acid leads to the higher rate constant and lower colorants half-life. The values of the rate constants are 2.50–4.25 times higher when the colorant degradation was run in the presence of 500 mg/L of ascorbic acid than in the case of the presence of 100 mg/L ascorbic acid for Brilliant Blue FCF, Chinoline Yellow, Patent Blue V and Tartazine. From the other side, the degradation of Brilliant Black BN and Indigotine is very fast with a total degradation for 6–9 days. Therefore, the rate constants for those two food colorants are much higher than for the other investigated colorants. According to the linearity of the kinetics curves (ln(c/co) v.s. time) it appeared to be first order kinetics for the interval up to 4 days.udud Key words: Food Colorants; Brilliant Black BN; Brilliant Blue FCF; Chinoline Yellow; Indigotine; Patent Blue V; Tartazine; ascorbic acid; degradation; kinetics rate constant; HPLC; UV-VIS spectrometryud