Abstract: The contents of amino acids in different cereals and ileal digesta were determined by reversed-phase high performance liquid chromatography (RP-HPLC) according to the AccQ-Tag method. The ratio of material to acidolysis agent was optimized in this paper. Quantification was performed using an internal standard method after pre-column derivatization with 6-aminoquinolinyl-N-hydroxysuccinimidate (AQC). The analysis procedure was carried out using a Waters 2695 HPLC system fitted with a Waters AccQ-Tag Nova-PakTMC18 column (3.9 mm × 150 mm, 4 μm) and a Waters 2475 fluorescence detector (Waters Corp., USA) at an excitation wavelength of 250 nm and emission wavelength of 395 nm at 37 ℃. Sodium acetate (pH 4.95), acetonitrile and water were used respectively as mobile phases A, B and C for gradient elution and the injection volume was 10 μL. The results showed that the optimum ratio of material to acidolysis agent was 1:100 (mg/μL). The calibration curves of 17 amino acids were linear within the range of 25?500 μmol/L (12.5–250 μmol/L for cystine) with correlation coefficients (r) of 0.999 6?0.999 9. The average recoveries were in the range of 97.56%–103.92% with relative standard deviation (RSD) of 0.31%?2.75% (n = 3). This method is rapid, simple and accurate for the determination of amino acids in cereals and ileal digesta.

Key words: reversed-phase high performance liquid chromatography (RP-HPLC), AccQ-Tag pre-column derivatization, cereals, ileal digesta, amino acids