Quantification of plasma S-adenosylmethionine and S-adenosylhomocysteine as their fluorescent 1,N(6)-etheno derivatives: an adaptation of previously described methodology.

A simplified reversed phase HPLC system for the detection of fluorescent 1,N(6)-etheno derivatives of SAM (S-adenosylmethionine) and S-adenosylhomocysteine (SAH) is described. The most important changes from the previously reported method are a shorter derivatization reaction time, the use of a solid-phase extraction resulting in an increase of the method's sensitivity, and the use of only one chromatographic system to separate SAM and SAH (in which the use of an ion-pairing reagent in the mobile phase is avoided). The linearity of the method was established, and the intra-assay coefficients of variation were 10.4 and 4.7% for SAM and SAH, respectively. Normal plasma values (n=8), evaluated with the present methodology, were, for SAM and SAH, respectively, 57+/-12 and 28+/-3 nM (mean+/-SD).