Simultaneous determination of pteridines in multicomponent mixtures using derivative spectrophotometry and partial least-squares calibration

Simple binary mixtures composed of very similar pteridines (neopterin and pterin) have been resolved by derivative spectrophotometry. Detection limits of 0.30 mu g ml(-1) and 0.12 mu g ml(-1) for pterin and neopterin, respectively, have been calculated. Also, different mixtures of pteridines considered as disease markers, such as pterin, neopterin, xanthopterin and isoxanthopterin, have been determined by using a partial least-squares (PLS-2) model. Calibration set containing 0-7 mu g ml(-1) for each component was used. The resolution of several mixtures and single determination was tested in artificial samples. (C) 1998 Elsevier Science B.V. All rights reserved.