Method for the analytical measurement of sample material on a sample support

A method for analysis of sample material deposited on a sample support surface comprises: (a) defining a plurality of regions on the surface, several of which are in contact with the sample material; (b) sampling sections of the sample within one of the regions by sweeping a desorbing beam along a selected non-rectilinear trajectory within the region while keeping the sample support surface in a fixed position, wherein the desorbing beam generates desorbed molecules that are ionised and transferred to an analyser; (c) transitioning from the swept region to another one of the regions to be swept using spatial adjustment of the sample support surface; and (d) repeating steps (b) and (c) until a predetermined condition is fulfilled. The desorbing beam may be an ion beam or a light beam. The analyser may be a mass analyser and/or a mobility analyser. A system for analysing ions, having an ion generation device and a control unit, is also disclosed.