Abstract: A capillary electrochromatographic method for the separation and analysis of organic acids in food was proposed using a capillary silica monolithic column. Optimization of experimental parameters that influence separation efficiency was carried out. A capillary silica monolithic C18 column was prepared in our lab for the separation of organic acids using a mobile phase (pH 5.2) consisting of 150 mmol/L sodium dihydrogen phosphate-60 mmol/L borax buffer solution with a final concentration of 5:2 in the mixture and 0.5 mmol/L cetyl trimethyl ammonium bromide. Other experimental conditions were as follows: voltage －6 kV; injection time 10 s; column temperature 25 ℃; and detection wavelength 200 nm. Results showed that the linear range was 10–1000 μg/mL for oxalic acid and fumaric acid, 20–500 μg/mL for succinic acid, 15–1000 μg/mL for tartaric acid and citric acid. The average recovery rates for the organic acids were between 89.8% and 101.1%, with a relative standard deviation (RSD) less than or equal to 6.23% (n = 5). The detection limits of the proposed methods were between 3.0 and 7.5 μg/mL. In conclusion, capillary silica monolithic column is inexpensive, stable to heat and organic solvents, and repeatedly usable. Capillary electrochromatography with capillary silica monolithic column allows simple, rapid and effective separation and analysis of organic acids in food.

Key words: food, organic acids, capillary silica monolithic column, capillary electrochromatography