Abstract:

A method for determining the content of carminic acid in cochineal extract was established using high performance capillary electrophoresis (HPCE). All experiments were carried out on an uncoated capillary column (60 cm × 75 μm, i.d.) under 20 kV and 0.5 psi × 10 s injection pressure at 25 ℃. The detection wavelength was set at 239 nm. Internal calibration method was used for quantification. Under all selected conditions, a good linear relationship of carminic acid was observed over the range of 50 to 500 mg/L, with a linear correlation coefficient of 0.9958. The average recovery rate of carminic acid in 7 parallel cochineal extracts spiked at a level was 100.86% and the detection limit was 5.00 μg/mL. This method is simple, rapid, accurate and can provide a reference for actual production.

Key words: high performance capillary electrophoresis (HPCE), carminic acid, content determination