Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to characterize the surface composition of mineral particles from concentrator and laboratory test samples, The surface composition of mineral particles ranging in size from 20-100 micrometers was established by probing a spot or by rastering a preselected area. The analytical depth resolution is sub-monolayer. Data presentation is in the form of positive or negative ion mass spectra and in the form of maps showing the distribution of elements or organic molecules, Activators, namely copper and lead, and oxidation products on sphalerite, pyrrhotite, pyrite and quartz from the Geco zinc concentrate, were detected and mapped. Amyl xanthate and di-isoamyl dithiophosphate on galena, from laboratory treated samples were detected and their distribution was mapped.