Comparative analysis of Raman and NIR spectroscopy

Comparative advantages
Advantages of NIR spectroscopy Advantages of Raman spectroscopy
  • No sample preparation required
  • Ease of measurement
  • High accuracy and reproducibility of analysis (accuracy of analysis is determined by the quality of spectra processing, end play and calibration accuracy of measuring mechanisms, calibration of the emission source)
  • No pollution
  • Measurability through glass and plastic packaging
  • Automatic measurement using OPUS software which requires a highly qualified specialist
  • Transfer of method from one device to another
  • Analysis of physical and chemical properties
  • No sample preparation required
  • Measurements of Raman spectra are much easier than those of NIR spectra due to more specified spectral characteristics and the absence of mechanical parts.
  • Spectra acquired by Raman spectroscopy, the most accurate of the existing measurement techniques, are considered as “fingerprints” of chemical substances. The absence of moving elements and independence of the Raman spectrum from the frequency and intensity fluctuations of the emitter ensure high reproducibility of measurements.
  • No pollution
  • Measurability through glass (including colored glass) and plastic packaging, identification of separate elements (drugs and packaging) being essentially more reliable than that of NIR spectroscopy.
  • Automatic measurement. The programming user interface enables operation of the Raman spectrometer by a non-technical user. The software is user-friendly, which is most significant for pharmaceutical and medical applications.
  • Raman spectra measured on two different instruments with the same spectral resolution always coincide, hence there is no problem of method transfer.
  • A more accurate analysis of the physical and chemical properties of the studied substances is possible since the NIR technique measures the overtones of fundamental oscillations, the direct acquisition of physical information from the energy and scattering cross sections of which is very difficult, if not impossible. Raman spectroscopy analyzes the fundamental vibrations of chemical molecules, the full information about which is either already available or can be obtained by simple experimental and theoretical methods

Instrument capabilities

NIR spectroscopy EnSpectr
  • Promptness of measurement ( 5-10 s)
  • Compact size
  • Spectral resolution determined by the width of the lines under study (about 100 cm-1)
  • Minimum amount of substance for analysis,  approx. 0.1 mg
  • No database. Only a few calibrated NIR spectra are available due to the novelty of the method. A large amount of work is to be carried out by qualified personnel to create a pharmaceutical database.
  • Promptness of measurement (within 1 s)
  • The EnSpectr portable Raman complex is much smaller in size and weight than a common NIR spectrometer.
  • Spectral resolution determined by the width of the lines under study (about 6 cm-1), which enables identification of a much larger number of substances.
  • Minimum amount of substance for analysis, approx. 0.001 mg (i.e., 100-times less) owing to the higher sensitivity of the receiver system in the visible range.
  • Well-thought-out method. Impressive database of calibrated spectra of pharmaceutical preparations and chemical substances.