Characterization of diffuse reflectance fiber probe sampling on moving solids using a Fourier transform near-infrared spectrometer

A characterization of the effect of sample movement on spectral response using an FT-NIR spectrometer is presented. The data were evaluated by means of both multivariate data analysis and visual inspection of interferograms and spectra. A fiber-optic probe was used to collect spectra from model samples such as paper, plastic and fine and coarse powders. During controlled movement at velocities between 0.046 and 0.73 m s-1, it was found that sample movement causes features not normally present in the interferograms. However, it is shown that after transformation to frequency domain single-beam spectra these artifacts are present well outside the near infrared spectral range (10,000¯4000 cm-1). The implication of these results is that FT-NIR is a suitable technique for process analysis of samples moving with low or moderate velocities.