Investigation of Tryptophan in Gastric Juice by High Performance Liquid Chromatography Coupling with Ultraviolet, Fluorescence Detection and Mass Spectrometric Identification

The HPLC-UV-Fluoreseence technique and HPLC-UV-MS technique were used to determine fluorescence molecule in gastric juice of patients with malignant gastric cancer, which is identified as tryptophan. Lidocaine was detected in gastric juice of patients who were examined by gastric endoscopy. A method was developed to determine concentration of tryptophan and lidocaine in gastric juice using HPLC-UV technique, in which Kromasil C-18 column (150 mm x 4.6 mm, 5 mu m) and methanol (containing 0.1% trifluoroacetic acid (TFA))-water(containing 0.1% TFA) as gradient mobile phase were used. The linear relationships were obtained between the concentration of tryptophan in the range of 0.5-200 mg/L and its peak area at 278 nm with correlation coefficient of 0.9994, and between the concentration of lidocaine in the range of 20-5000 mg/L and its peak area at 254 nm with correlation coefficient of 0.9992. The limit of detection is 0.15 mg/L for tryptophan and 5 mg/L for lidocaine. The recovery is 70.8%-110.4% for tryptophan and 87.1%-116.2% for lidocaine. 38 gastric juice samples of patients with malignant gastric disease and 48 gastric juice samples of patients with benign gastric disease were tested and the concentration of tryptophan in those two groups of gastric juice samples was apparently different.