Abstract: MCR provided estimated pure component time series spectra as extracted from infrared or other spectroscopy is capable of being compared to spectra in a reference library to find the best matches. The best match spectra can then each in turn be combined with the reference spectra, with the combinations also being screened for best matches versus any one of the estimated pure component time series spectra. These resulting best matches can then also undergo the foregoing combination and comparison steps. The process can repeat in this manner in an unbounded fashion if desired until an appropriate stopping point is reached, for example, when a desired number of best matches are identified, when some predetermined number of iterations has been performed, etc. This methodology is able to return best-match spectra with far fewer computational steps and greater speed than if all possible combinations of reference spectra are considered.