METHOD FOR OBTAINING IONS FOR THE INVESTIGATION, BY MASS SPECTOMETRY, OF THE MOLECULAR STRUCTURE OF A NORMALLY SOLID AND NON-VOLATILE COMPOUND

摘要

In mass spectrometry, the conventional methods of ionisation are unsuitable or of low efficiency for substances which are normally solid and which cannot be evaporated in a stable form. Such substances, which include many compounds of biomedical importance, are amenable to a method of ionisation in which the compound is subjected to bombardment by a beam of neutral atomic particles. A target coating is produced in which a sample of the compound is present in a mobile state at the surface of the coating and the atomic beam is supplied at a low angle which is within a typical range of 10 DEG to 30 DEG , relative to the surface. The kinetic energy of the beam concerned is such that, during the mass analysis, a range of ion species which comprise both pseudo-molecular ions and structurally significant fragment ions is observed or detected. The mobile state may be the molten state or a solution in a carrier of low volatility, such as glycerol. IMAGE