A low-voltage, high-resolution mass spectrometric (LVHRMS) method for analyses of complex materials, such as coal-derived liquids, Is presented. Descriptions of the computations utilized to convert LVHRMS spectra to weight percent data on Individual compound types and the associated computer software are reported. Elemental analyses, carbon number distributions, number average molecular weights, and a measure of aromaticity have been determined for 10 distillate fractions derived from an H-Coal liquid by this technique, and the results were compared with those obtained by classical methods. The changes in distribution of the principal compound classes over the range of distillates can readily be followed. The LVHRMS method described can be applied to other complex materials containing heteroatoms.