Abstract

The limitations inherent in the traditional method of preparation of coal for examination by infrared spectroscopy, i.e. the alkali halide disc method, are well documented. Friedel <i>et al.</i> clearly showed the need for fine and, therefore, prolonged grinding to produce acceptable spectra and demonstrated how this produces the KBr/H₂O interaction bands that mask the —OH stretching bands. Painter <i>et al.</i> avoided these problems by grinding the coal in fluorolube following the method described by Brady. This, however, left a strongly sloping base line that could be partially overcome by standard base line correction procedures available on computerized instruments. The difficulties experienced in measuring the hydroxyl functional groups in coal were also discussed by Painter <i>et al.</i> in a later paper and it was concluded that a combination of Fourier transform infrared (FT-IR) and chemical procedures was required.

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