An accurate and sensitive analytical method for the simultaneous determination of glycine, methionine and homocysteine in biological matrices by matrix matching strategy and LC-quadrupole-time-of-flight-MS/MS.

Nowadays, it is well known that early diagnosis directly affects the success of treatment. Biomarkers play a crucial role in early diagnosis of diseases or explanation of pathological condition. The investigation of new biomarkers depends on the reliable quantification of analytes in biological matrices. Regarding to the critical roles of amino acids in metabolism, functions and nutrition of human body, the careful monitoring of their levels in biological samples is required to evaluate their potential in biomarker studies for clinical research. In this study, a reliable and accurate analytical strategy was developed for the simultaneous determination of glycine, methionine and homocysteine using LC-quadrupole-time of flight-tandem MS system. The method detection limit was found to be 0.73 μg/mL, 0.017 μg/mL and 0.019 μg/mL for glycine, methionine and homocysteine, respectively. The calibration curves were obtained with great linearity (R ≥ 0.9993) and low relative standard deviation values showed the repeatability of proposed method. The method applicability was determined using human plasma and urine samples, and high percent recoveries demonstrated the accuracy of method developed. Each measurement was taken less than 4.0 min indicating a promising strategy for the fast and reliable quantification of target amino acids in clinical laboratories.