(n = 1, 3, 5) and Bi3 ++ in high current bunch mode was employed, with a current ranging between 0.05 and 1 pA. The actual data acquisition was performed over a surface area of 150μm × 150μm. The operation was carried out using a cycle time of 150 μs resulting of an 0-1800 m/z mass range. The analysis time was of 2 minutes for each sample and a charge compensator was used to avoid charges accumulation on the sample surface. These parameters were specifically selected to optimize the detection of clusters of high mass.