Determination of S-Adenosylmethionine and S-Adenosylhomocysteine in Human Urine by Ion Chromatography with Solid Phase Extraction Based on the Application of Micromolecule Ion-Pairing Agent

S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) play an important role in various biochemical reactions involving the maintenance of human health and disease prevention. In this study, an accurate, rapid, economical, and simple protocol is reported for the simultaneous determination of the SAM and SAH concentrations in human urine. 97% trifluoroacetic acid (0.05%) was used in the mobile phase as a micromolecule ion-pairing agent in order to enhance the formation of ion pairs and the protonation of the SAM and SAH analytes. Following solid phase extraction (SPE), the separation of SAM and SAH was performed by micromolecule ion pair chromatography using a C18 column. Three types of solid phase extraction columns were characterized for the purification of the urine samples, and their correlative mechanisms were evaluated in detail. Good linearity values were obtained across the concentration ranges from 0.5 to 60 mu mol/L and 0.1 to 10 mu mol/L for SAM and SAH, respectively. The limits of detection were equal to 0.006 and 0.01 mu mol/L for SAM and SAH, respectively, while the limits of quantitation were 0.02 and 0.04 mu mol/L for these analytes. The intra-day and inter-day precision values for the determined SAM and SAH species were less than 1.38. The recovery values of SAM and SAH in urine were between 83.65 and 98.41%. Thus, this method has demonstrated to be suitable for the determination of SAM and SAH in human urine.