This article describes the analysis of synthetic dyes in food samples using capillary zone electrophoresis with an alkaline phosphate buffer as the background electrolyte. The precision of the method was found to have 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 individual dyes was approximately 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.
The document details an analytical method for separating common synthetic dyes, such as amaranth, sunset yellow, and tartrazine, in food samples. The study utilizes capillary zone electrophoresis (CZE) with an alkaline phosphate buffer as the background electrolyte to achieve high precision in migration times and peak areas.
The analysis was performed using an Agilent CE system equipped with a built-in diode-array detector and ChemStation software. Separations were achieved using fused-silica capillaries with extended path length or bubble cells, operating at 30°C with a specific sodium phosphate buffer mixture. The method allows for detection at multiple wavelengths (215, 410, 520, and 598 nm) and confirms dye identities through spectral library matching and peak-purity routines.
The detection limit was about 1 ng when using a specific capillary.
Capillaries must be flushed with sodium hydroxide for 3 minutes followed by buffer for 10 minutes.