[Determination of isoxanthopterin in human urine by solid phase extraction-high performance anion-exchange...

A sensitive, selective and environmental friendly method for the determination of isoxanthopterin in human urine by solid phase extraction (SPE)-high performance anion exchange chromatography (HPAEC) with integrated pulsed amperometric detector has been developed. The tandem solid phase extraction was employed to purify isoxanthopterin from human urine. The separation of isoxanthopterin was carried out on an IonPac AS21 anion-exchange column with eluent of 0.025 mol/L NaOH at the flow rate of 0.40 mL/min. Under the optimized conditions, the detection limit for isoxanthopterin was 0.003 mg/L, and the linear range was 0.005-0.200 mg/L. The spiked recoveries ranging from 95.4% to 96.8% were obtained in the urine samples from healthy persons and cancer patients, and the relative standard deviation (RSD) was less than 5%. The present method was successfully applied to the determination of isoxanthopterin in urine from healthy individuals and cancer patients.