8 New Trend in Instrumentation of NIR Spectroscopy …
205
profile of a given miniaturized spectrometer in a comprehensive way. Yet, to be
able to fully predict even approximate performance in a given application, extensive
and tedious analyses of numerous samples are necessary. To mitigate this imitation,
quantum chemical simulations of NIR spectra are helpful. Firstly, detailed NIR band
assignments enable linking the wavenumber regions that are established as meaningful in the chemometric models with the vibrational modes of the target molecule.
This allows to interpret the regression vectors and to assess the sensitivity of a spectrometer toward specific modes. More importantly, through these steps, the ability
to generalize the performance over a wider range of scenarios is given. For instance,
the performance against certain classes of analytes can be predicted following their
likeliness of appearing characteristic NIR bands within the sensitivity ranges of a
given spectrometer. This can be obtained without the need to perform analyses of
large number of analyses, or even measurement of standards. Furthermore, the influence of matrix effects on various vibrational modes can be obtained through quantum
mechanical calculation of NIR spectra [10, 16, 17]. The scheme presenting the gains
from combined approaches to comprehensive evaluation procedures of miniaturized
spectrometers is presented in Fig. 8.7.
Fig. 8.7 Methods useful for comprehensive dissection and comparison of performance profiles
of NIR spectrometers that are based on various design philosophies and differ in their operating
characteristics
205
profile of a given miniaturized spectrometer in a comprehensive way. Yet, to be
able to fully predict even approximate performance in a given application, extensive
and tedious analyses of numerous samples are necessary. To mitigate this imitation,
quantum chemical simulations of NIR spectra are helpful. Firstly, detailed NIR band
assignments enable linking the wavenumber regions that are established as meaningful in the chemometric models with the vibrational modes of the target molecule.
This allows to interpret the regression vectors and to assess the sensitivity of a spectrometer toward specific modes. More importantly, through these steps, the ability
to generalize the performance over a wider range of scenarios is given. For instance,
the performance against certain classes of analytes can be predicted following their
likeliness of appearing characteristic NIR bands within the sensitivity ranges of a
given spectrometer. This can be obtained without the need to perform analyses of
large number of analyses, or even measurement of standards. Furthermore, the influence of matrix effects on various vibrational modes can be obtained through quantum
mechanical calculation of NIR spectra [10, 16, 17]. The scheme presenting the gains
from combined approaches to comprehensive evaluation procedures of miniaturized
spectrometers is presented in Fig. 8.7.
Fig. 8.7 Methods useful for comprehensive dissection and comparison of performance profiles
of NIR spectrometers that are based on various design philosophies and differ in their operating
characteristics