Direct identification of organic inclusions in graphite on the basis of field desorption mass spectrometry

A method for the direct identification of organic inclusions in graphite on the basis of field desorption mass spectrometry is proposed, based on the possibility of using a fractured graphite sample as a field emitter. Under such circumstances, the organic inclusions adsorbed on the surface of the microcrystallites of modified graphites may be directly field desorbed and identified by their mass spectra without any pretreatment of the sample. Two differently modified types of graphite were analysed by this method and the nature of the admixtures was established: one sample appeared to contain a mixture of polymethylsiloxanes and the other and blend of dyes. For the latter sample, temperature fractionation of admixed substances was performed and the presence of three individual dyes was established. Such features of field desorption as the production of abundant molecular ions with negligible fragmentation and the possibility of obtaining of mass thermograms greatly facilitate the identification of individual components of mixture inclusions.