Theoretical and technical advancements of near infrared spectroscopy and its operational impact in industry

Author Summary: In the industrial environment, near infrared spectroscopy (NIRS) on one hand enjoys increasing popularity due to its defined advantages over classical analytical techniques (e.g. chromatography) including fast, non-invasive and simultaneous determination of several physical and chemical parameters. On the other hand, hardly any other analytical discipline is making such fast and fundamental technical and theoretical advancements. Miniaturization of spectrometers down to light weight portable devices is achieved via micro-electro mechanical systems (MEMS) or linear variable filter (LVF) instruments, operating with restricted performance in a defined wavenumber range. Fast NIR imaging devices are becoming popular checking conformity and spatial distribution of ingredients. NIRS is also benefiting from theoretical advances including design of experiment (DOE) for systematic optimization purposes, special algorithms for calibration transfer between different types of spectrometers, and last but not least, quantum chemical approaches are becoming essential for distinct band assignments especially in case of complicated combination and overtone vibrations. Care must be taken about how these advancements can be successfully applied in the industrial environment.