Simultaneous fluorimetric determination of pteridin derivatives: Comparison between synchronous, partial least-squares, and hybrid linear analysis methods

Several methods are described for the simultaneous determination of binary mixtures of xanthopterin (XAN) and isoxanthopterin (ISO) and of binary mixt ures of xanthopterin and biopterin (BIO), The total luminiscence! informati on from each compound has been used to optimize the most adequate analytica l signal. A synchronous spectrofluorometric univariate procedure to analyze XAN and ISO is proposed. The procedure is compared with two multivariate p rocedures based on partial least-squares (PLS-1) and hybrid linear analysis (HLA/XS), by using synchronous spectral data as analytical signals. For th e resolution of binary mixtures of XAN and BIG, a comparison between the pr edictive ability of the multivariate calibration methods, PLS-1 and HLA/XS, on two spectral data sets, excitation and emission spectra, has been perfo rmed. The calculation of the net analyte signal (NAS) by the HLA/XS method allows the determination of selectivity and sensitivity in each case. The p roposed procedures are validated in the determination of several mixtures o f these compounds, and the error values in a test set are reported.