The field of molecular vibrational spectroscopy applied to medicinal plant analysis is developing very dynamically. Even though, traditional separation and mass spectrometric (MS) techniques offer analytical investigations with high selectivity and sensitivity, vibrational spectroscopy benefits from the short analyses times, non-invasiveness and the simultaneous analysis of chemical and physical parameters.
Furthermore, chemometric univariate and multivariate data treatment enables efficient spectral interpretation and the establishment of sufficient calibration/validation models. Advanced quantum chemical approaches can further support the challenge of band assignment [1]. Near-infrared (NIR, 4.000-10.000 cm-1), attenuated total reflection (ATR, 400-4.000 cm-1) and Raman spectroscopy have been demonstrated as being very efficient for even complex qualitative and quantitative attempts in combination with selective reference analytical methods. Qualitative attempts comprise analysing, e.g., species and in some cases also origin, quantitative analysing chemical and physical parameters. Two-dimensional correlation spectroscopy (2D-COS) has been developed towards a powerful analysis tool for monitoring the dynamics of a spectrometer system [2]. The miniaturization of spectrometers is a highly demanding trend, enabling to carry out investigations at any independent place including the field [3]. Imaging and mapping spectroscopic attempts (MIR, NIR, Raman) enable high-resolution analysis of potent ingredients down to approximately 4 µm and 1 µm, respectively [4].
This contribution highlights recent advances of molecular spectroscopy in medicinal plant research. The latest technical developments will be discussed followed by several selected applications. Their limits and advantages over traditional methods will be critically evaluated to point out the future trends.
This work was supported by the Austrian Science Fund (FWF), P32004-N28, and by the Federal Ministry of Ministry of Education, Science and Research (Vienna, Austria) (Novel analytical tools for the quality assessment of Chinese herbs with metabolic, immune related neuromodulatory effects, BMBWF-402.000/0017-WF/V/6/2016).
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