Efficient recovery of electrophoretic profiles of nucleoside metabolites from urine samples by multivariate curve resolution.

Chemometric techniques usually employed in purity assessment and resolution of multicomponent peaks have been applied to analytical data from complex biological samples obtained with CE-DAD. In the assessment of the purity of the electrophoretic peaks, the orthogonal projection approach, the orthogonal projection approach with Durbin-Watson criterion, and the simple-to-use interactive self-modeling mixture analysis method have been employed. Multivariate curve resolution with alternating least squares has been successfully implemented to resolve co-migrating peaks of metabolites in CE-DAD and to recover qualitative and quantitative information about co-migrating components of urine extract. The main challenge consisted of developing high-quality multivariate curve resolution with alternating least squares models of multicomponent peaks acquired during the CE analysis of nucleoside patterns in 18 urine samples. The recovered ultraviolet visible (UV-Vis) spectra have been employed to identify additional nucleosides, such as 1-methylinosine, 2-methylguanosine, and 1-methylguanosine, whose presence in the metabolic profile produced by the applied CE-DAD method has not yet been recognized. Concentration profiles of these compounds can be used in metabonomic studies.