Determination of isoxanthopterin in human urine by synchronous fluorescence scan

A synchronous fluorescence method was studied to determine the isoxanthopterin in human urine.The measurement was carried out in a KH2PO4-NaOH buffer solution(pH 7.8) with Δλ=65 nm for synchronous scanning,which can exclude interferences of other substances in urine samples.The linear range for the concentration of isoxanthopterin was found to be 0～1.4 μg/mL.The linear regression equation was I=4105.3ρ+59.696,with linear correlation coefficient of 0.9997.Both healthy people′s urine samples and patients′ urine samples were measured.For healthy people,the recoveries were in the range of 102.9%～108.%,the relative standard derivations(RSD) were 0.37%～1.2%,while for the patients′ recoveries were in the range of 85.6%～95.6%,and the RSD were 1.0%～2.2%.The proposed method was successfully applied to the determination of isoxanthopterin in human urine samples.