QUANTITATIVE-ANALYSIS IN DIFFUSE-REFLECTANCE SPECTROMETRY - A MODIFIED KUBELKA-MUNK EQUATION

The behaviour of the Kubelka-Munk equation with particle size is analy sed by using mono-disperse polystyrene particles. Based on the experim ental results a model is proposed to explain the diffuse reflectance s pectra of powdered samples in a quantitative manner. The new model exp lains quantitatively the behaviour of the diffuse reflectance spectra of mono-disperse polystyrene particles in KBr. Furthermore, the result s show that the model can be used to explain the diffuse reflectance s pectra of mixtures of mono-disperse polystyrene spheres in KBr and of a coal sample mixture containing a distribution of particle sizes and KBr. It appears that the proposed model can be used for dilute samples in a quantitative manner.