Determination of Endogenous Metabolites in Obesity Rat Urine by Pressurized Capillary Electrochromatography with Ethyl Chloroformate Derivatization

Pressurized capillary electrochromatography (pCEC) method was developed to analyze metabolites in normal and obesity rat urine with ethyl chloroformate derivatization. The separation was performed on a capillary column (EP-150-30/50-5-C18), and good resolution was obtained with the mobile phase of water (0.01% TFA)−95% acetonitrile (0.01% TFA) using the following gradient: 0–30 min, 0–50 % B; 30–40 min, 50%–75% B. Under the optimized conditions, such as pressure of 13000 kPa, applied voltage of 2 kV, flow rate of 0.08 ml min−1, and room temperature, the contents of metabolites in the urine of normal and obesity rats were obtained. Under the optimum conditions, the correction coefficients were 0.9988–0.9999 in the range of 1.25–500 g l−1. The intra- and inter-day precisions were less than 5%. The average recoveries ranged from 95.9% to 103.2%. The method is simple, sensitive, and accurate for the determination of endogenous metabolites in rat urine sample.