Interpreting complicated chromatographic patterns.

GC-MS, HPLC, automatic amino acid analysis, high-resolution two-dimensional electrophoresis and capillary electrophoresis are suitable for the multicomponent analysis of body fluids and tissues. Manual interpretation of the complex metabolite and protein profiles thereby obtained is usually difficult, except in the case of metabolic disorders, where major deviations from the normal profiles often are observed. Implementation of multivariate data analysis makes it possible to retrieve diagnostic information that otherwise may be overlooked, as shown in this report where patients with leprosy have been examined. Urine samples were analysed by ion-exchange chromatography and by GC-MS to obtain profiles of amino acids and organic acids. Qualitative and quantitative information on 68 metabolites were then analysed by principal components analysis (PCA) and by partial least square models (PLS). Three different PLS dimensions were found (cross-validation) corresponding to controls (persons without leprosy), paucibacillary and multibacillary leprosy.