Abstract:

A new method for the simultaneous determination of ten synthetic food colorants in alcoholic beverages
and candies by capillary electrophoresis (CE) with photodiode array (PDA) detection was established. The
separation was carried out using an uncoated capillary with 75 μm (i.d.) and total length of 70 cm (60 cm to the
detector) within 25 min. The separation voltage was 18 kV. The detection wavelength was set at 214 nm. The
key factors that affect the separation such as the concentration and pH of the running buffer, the concentration
of additives were investigated in detail. The alcoholic beverage was directly injected after filtration. The candy
sample was first ground and then extracted with sample buffer. The extract was centrifuged and the supernatant
could be directly injected. Good linear relationships between the corrected peak areas and mass concentrations
of the ten synthetic food colorants were obtained in the range of 1.0–40.0, 1.5–60.0, 2.0–80.0, 3.0–120.0 mg/L,
respectively, with correlation coefficients all above 0.999 6. The limits of detection (RSN =3) were 0.3–1.0 mg/L,
and the limits of quantitation (RSN =10) were 1.0–3.0 mg/L, respectively. The average recoveries were between 92.1%–
106.5% with relative standard derivations of 0.5%–4.4%. This method is simple and accurate. It can be applied to the routine
analysis of 10 synthetic colorants in alcoholic beverages and candies.

Key words: synthetic colorants, candy, alcoholic beverages, capillary electrophoresis