Analysis of Synthetic Dyes in Food Samples by Capillary Zone Electrophoresis Application Note

Synthetic food dyes were separated by capillary zone electrophoresis using an alkaline phosphate buffer as background electrolyte. The precision had a relative standard deviation of less than 0.5 % for the run-to-run migration times and 2 % for the peak areas with buffer replenishment after each run. The detection limit for the individual dyes was about 1 ng using a 50-μm internal diameter Agilent extended path length capillary. Compounds were detected at different wavelengths— 215, 410, 520 and 598 nm—and the identities of the individual dyes were confirmed using peak-purity routines and a UV-Visible spectral library.