Current frontiers in quantum chemical simulations of NIR spectra – Polymers, biomolecules, aqueous matrix and interpretation of instrumental difference of handheld spectrometers

Abstract

Analytical near-infrared (NIR) spectroscopy has developed rapidly over the past few decades and is today of incredible value for academic, industrial and institutional laboratories. These developments are closely related to the development of instruments and miniaturization, as well as the methods of multivariate analysis. The strong stimulus for the development of NIR spectroscopy originating from the application field resulted in the advancement of this technique to suite unitarian goals. By contrast, less actively explored have been the foundations of NIR spectroscopy. Much of the information contained in the NIR spectrum is still not easily accessible for the purpose of basic research. In the past few years, a promising development has been made in application of the methods of computational chemistry to NIR spectroscopy. In this article, the current frontier of this advancement is summarized. The scope of the recent accomplishments shifts closer to the challenging real-life problems, such as interactions of the analysed molecules with the matrix, including the aqueous environment. Particular attention was given to the interpretation of the chemical factors underlying instrumental differences between miniaturized NIR spectrometers using different technology and optical solutions. The applicability of the methods of computational chemistry to unravel intricate NIR spectral features of complex molecules such as biomolecules and polymers should be highlighted as well.