Letter: Practical Consequences of Math Pre-Treatment of near Infrared Reflectance Data: Log (1/R) vs F(R)

Abstract

The selection of F( R) or (1/ R) as the metric for quantitative diffuse reflection spectrometry depends on the application and on the spectral region. For mid-infrared measurements, where dilution in a non-absorbing matrix is usually necessary and samples are often physical mixtures of the individual components, the use of the Kubelka–Munk function, F( R), is often preferred. For diffuse reflection measurements of agricultural products and commodities in the near infrared region, where dilution in a non-absorbing matrix is unnecessary and the concentration of the analytes rarely varies by more than a factor or two, the use of log(1/ R) is preferable. For any diffuse reflection measurement where the spectral baseline is irreproducible, band intensities vary with the baseline in F( R) spectra but not in log (1/ R) spectra.