Application of the BTEM family of algorithms to reconstruct individual UV–Vis spectra from multi-component mixtures

The BTEM family of algorithms, BTEM, tBTEM and MREM, were successfully applied to reconstruct the pure component spectra from broad and highly overlapping in-situ UV–Vis spectra. Ten spectra of cell plus water and dye solutions were collected in one semi-batch experiment. In this experiment multiple perturbations of three dyes, namely bromophenol blue, bromocresol green and methyl orange were performed. Good estimated pure spectra, compared to experimental references, were recovered by the application of these three algorithms without recourse to a priori information. Reasonable concentration profiles of the three dyes, compared to their corresponding real concentrations, were achieved by multivariate least square analysis. This contribution demonstrates that: (i) a many-spectra-at-a-time survey of underlying spectral estimates is possible to achieve via the application of MREM without any supervision; and (ii) the BTEM family of algorithms can recover accurate UV–Vis spectral estimates using only non-negativity constraints for absorptivities.