The study of decomposition of explosives is the study of fundamental chemical reaction pathways. This knowledge is important in many fields. Examples are evaluation of risks concerning handling and long time storing, modelling of initiation and burn characteristics, risk evaluations and the tailoring of new energetic materials. A time of flight mass spectrometer equipped with a fused silica capillary column inlet has been use for the study of the "ADN anomaly", the onset of a minor decomposition reaction for dry ADN at a temperature of 60-65 ºC. Initial results are presented. A new method for decomposition studies is currently being set up and applied on RDX decomposition intermediates. This method - matrix isolation spectroscopy - has the advantage of being able to capture short lived chemical species, such as reaction intermediates, and keep them in a cold, inert matrix to allow for spectroscopic investigations. The method can also provide structural information about molecules. Matrix isolation will be an important complement on today´s experimental methods, and can be used for the decomposition studies of new energetic materials.