A simple and reliable ultra-high performance liquid chromatography coupled with tandem mass spectrometry method for simultaneous quantification of tyrosine and its metabolites in human urine

In this paper, a fast and reliable method was developed for simultaneous quantification of tyrosine, 4-hydroxyphenyl acetic acid, 4-hydroxyphenyl lactic acid, 3-4-hydroxyphenyl propionic acid, 4-hydroxyphenethyl amine and 3-4-hydroxyphenyl alanine in human urine by ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS). The sample preparation procedure was simplified to obtain a fast analysis in terms of diluting the urine with ultrapure water and centrifuging pre-analysis. After estimating the matrix effect, matrix-matched calibration curves were used to equalize the matrix effect, and both chromatographic and MS conditions were optimized. To verify the reliability of this method, the performances of this method were validated carefully in terms of accuracy, precision, linearity, sensitivity, stability and carryover effect. The validation results showed that, the calibration cures were linear (correlation coefficients above 0.999), and the limits of detection and limits of quantification for the analytes were in the range of 0.003–0.081 mg/L and 0.010–0.270 mg/L, respectively. The recoveries were in the range of 85.5–110.0%, with RSDs of 0.8–4.2%. This method was further applied to human urine samples from normal people and cancer patients. All the results showed that this study might be helpful for development of noninvasive methods for cancer biomarkers discovering.