Comparison between conventional spectral analysis methods, chemometrics, and two-dimensional correlation spectroscopy in the analysis of near-infrared spectra of protein

The present study has aimed at comparing three methods for analyzing near-i nfrared (NIR) spectra: conventional spectral analysis methods, chemometrics , and generalized two-dimensional (2D) correlation spectroscopy, In a compa rison of these approaches, NIR spectra were measured for aqueous solutions of human serum albumin (HSA) with the concentration range of 0.5-5.0 wt %. Synchronous and asynchronous 2D correlation spectra were generated from the concentration-dependent NIR spectral variations of HSA in distilled water. The first and second loadings plots were calculated for principal componen t analysis (PCA) models based upon the above NIR spectral data. It was foun d that slice spectra calculated from the synchronous spectra are very close to the first loadings plots and that slice spectra from the asynchronous s pectra have a close resemblance to the second loadings plots. The reasons w hy the synchronous and asynchronous spectra bear close resemblance to the f irst and second loadings plots for the PCA model, respectively, are discuss ed in the paper.