Purity assessment and resolution of tetracycline hydrochloride samples analysed using high-performance liquid chromatography with diode array detection

High-performance liquid chromatography with diode array detection (HPLC-DAD ) was used for the analysis of a tetracycline hydrochloride sample (TC-HCl) . The analytical search for impurities in TC-HCl is complicated, because th e standards are not always available and because unexpected impurities are produced by new mutants during fermentation. Due to this it is useful to ch eck the purity of the peaks in the chromatogram even when it is obtained wi th an optimised analytical technique. The homogeneity of the individual pea ks in the HPLC-DAD chromatogram was checked using chemometric methods such as the orthogonal projection approach (OPA) and the fixed size moving windo w evolving factor analysis approach (FSW-EFA). After the selection of the n umber of components, the experimental data were resolved in the pure compon ent spectra and the individual concentration profiles. The multivariate cur ve resolution alternating least-squares approach (MCR-ALS) was applied for this purpose on the single HPLC-DAD chromatograms (two-way data) and on set s of such chromatograms (three-way data). (C) 1999 Elsevier Science B.V. Al l rights reserved.