Rapid high-performance liquid chromatography method for determination of tryptophan in gastric juice

OBJECTIVE: To develop a rapid, high-performance liquid chromatography (HPLC) method for the determination of tryptophan in gastric juice to help the differentiation between gastric cancer and benign gastric disease. METHODS: HPLC was performed on a restricted access material Shiseido Capcell Pak MF SCX SG80 column. Phosphate buffered solution (90 mmol/L, pH 3.5)-acetonitrile (ACN; 80/20, V/V) was chosen as the mobile phase. Separation was done at room temperature using a constant flow rate of 1.0 mL/min. Fluorescence emission signal intensity at 330 nm excited by 288 nm ultra violet light was detected and measured. RESULTS: Thirty-eight gastric juice samples from patients with gastric cancer and 48 gastric juice samples of patients with benign gastric disease were tested. A linear relationship in the range of 0.20–100 mg/L was obtained between the concentration of tryptophan and its fluorescence emission signal intensity at 330 nm. The limit of detection was 0.05 mg/L. The recovery rate was 77.4–90.6%. CONCLUSIONS: An HPLC method based on strong cation-exchange restricted access columns for determination of concentration of tryptophan in gastric juice was developed. The method has excellent precision and stability. It is compatible with the analysis of gastric juice and has the potential to be used for gastric cancer screening.