For dextrin to interact with pyrite, metal oxidation species are required on the surface. A surface cleaned of such species did not adsorb dextrin while after oxidation or doping with metal ions, dextrin did appear on the surface. The type of metal ion may not be important, however; doping with both Fe and Pb ions promoted adsorption. This may have implications for selective depression using dextrin, as mineral surfaces in practice are often contaminated with a similar variety of metal ions derived from the other minerals.