Determination of Plasma Homocysteine with a UHPLC-MS/MS Method: Application to Analyze the Correlation Between Plasma Homocysteine and Whole Blood 5-Methyltetrahydrofolate in Healthy Volunteers.

An ultra-high performance liquid chromatography tandem mass spectrometry method was developed for determination of homocysteine (HCY) in human plasma. The HCY was derivatized with 2-chloro-1-methylquinolinium tetrafluoroborate and isolated using solid-phase extraction. Derivatization, isolation and detection procedures were optimized. Satisfactory linearity was obtained with determination coefficients (r(2)) >0.999. The intra- and inter-day precisions were in the interval of 1.2-5.1% and accuracy was within +/- 7%. Mean recoveries were close to 100%. The limit of detection and the limit of quantification were 0.46 and 1.38 mu mol/L, respectively. The method was then applied to investigate the relationship between plasma HCY and whole blood 5-methyltetrahydrofolate levels in healthy volunteers. The results revealed that the plasma level of HCY was significantly negatively correlated to whole blood 5-methyltetrahydrofolate in volunteers.