Partial least-squares calibration of two-way diode-array high-performance liquid chromatograms: influence of calibration design, noise and peak separation

An approach for the calibration of two-way diode-array high-performance liquid chromatograms is described, involving unfolding a three-way data matrix and performing partial least-squares (PLS) calibration. The properties of loadings summed over time and wavelength are discussed. The influence of calibration design, noise levels and peak separation are investigated, using pseudosimulations, both by calculating prediction and test errors and by graphical representation of the summed loadings. The importance of using an independent test set is emphasized. Calibration design is shown to have a major effect both on the appearance of the loadings and on the PLS errors.