For negative-ion laser desorption/ionization mass spectrometry only a small number of sample preparation methods for coal exist, which suffer from low sample capacities. Therefore, a new sample preparation method is presented in this work. The sample is applied to a target as a dispersion of coal in glycerol or poly-ethylenglycol 400 and water. Measurements of these preparations show high sample capacities, are stable and produce good reproducible results.