Simultaneous analysis of homocysteine and methionine in plasma

The new isocratic cation exchange method separates up to eight different am ino thiols. The separated sample components are detected electrochemically using a gold electrode and the integrated pulsed amperometry. The eluent co mposition is, for example, 0.15 M sodium perchlorate, 0.02 M perchloric aci d and 5% acetonitrile. The report describes the optimization of chromatogra phic parameters such as column diameter and eluent composition. Quantitativ e performance is discussed for eight different amino thiols using standards . Also presented is a long term quantitative study for homocysteine and met hionine in plasma samples. The preparation of plasma samples is simpler tha n with the previously reported version of the method. Only a reduction step is required, and neither column switching nor derivatization are necessary . (C) 2001 Elsevier Science B.V, All rights reserved.