Study On The New Analytical Method Of Pterins And Amino Acids In Rat Urine

The literature shows that pterins and amino acids are of great significance to organism metabolism. The literature also indicates that analyzing the change of pterins and amino acids in the organism might provide important reference value for the early diagnosis of cancer. This paper reviewed the reports of pterins and amino acids on the determination method, sample preparation procedure and relationship to illness. We established methods of IC-FLD and HPLC-MS/MS to measure the concentrations of pterins and amino acids in rat urines, then choosed the IC-FLD methods to analyze the rat urine samples of bladder cancer model group and control group to search for the potential tumor markers. In general, main research results are as follows:1. Simultaneous determination of tryptophan, Tyrosine and Pterin-6-carboxylic acid in rat urine by ion chromatography with fluorescence detector has been developed. After the protein were removed with trichloroacetic acid, the rat urine samples were purified on a MAX solid phase extraction column, then detected by IC-FLD. The limits of the instrument detection of the three analytes were 0.08,0.3 and 0.002 μmol/L, respectively. The recoveries were in the range of 71.2%~121.7%, with the coefficient of variation lower than 11.7%.2. A simple, rapid and sensitive method for the simultaneous determination of xanthopterin, isoxanthopterin, pterin-6-carboxylic acid, tyrosine and tryptophan in mouse urine by HPLC-MS/MS has been proposed. After the protein were removed, the mouse urine samples were diluted 50 times and then detected by HPLC-MS-MS directly. The influence of the matrix was eliminated by using the matrix standard curve. The limits of the instrument detection of the five analytes were 1.6,1.5,2.2,0.9 and 1.0 ng/m L, respectively. The recoveries were in the range of 89.0% ~107.0%, with the coefficient of variation between 0.30% and 5.19%.3. The ion chromatography method has been applied to the simultaneous determination of trytophan, tyrosine and pterin-6-carboxylic acid in rat urines of bladder cancer group and control group. The determination results showed that the average level of the three analytes had different change trends with the growth of the tumor. Trytophan and pterin-6-carboxylic acid might be used as potential biomarkers for noninvasive diagnosis of different stage of bladder cancer. However, more data are needed to support this hypothesis.