Determination of synthetic colourant food additives by capillary zone electrophoresis

A capillary zone electrophoresis method for the separation of six synthetic food colourants is proposed. A background electrolyte solution consisting of 20 mM berate buffer adjusted to pH 7-9 and electromigration injection at 4 kV for 14 s were utilized. A baseline separation of six synthetic colourants commonly used as food additives can be achieved within 10 min, and a linear relationship between the concentration and peak area for each of these pigments was obtained in the concentration range 2-50 ppm, with a correlation coefficient greater than 0.995. The selection of the analytical conditions and the experimental reproducibility are discussed.