We present a combination of acoustic wave based sensors with scanning probe microscopy as a tool for better understanding the interaction of the former with the surrounding viscous medium when used for detection of analytes in liquids. Simultaneous analysis of the gold coated sensing surface with an atomic force microscope and monitoring changes in the acoustic propagation properties during copper electrodeposition provides a mean of correlating observations on the nanometer and millimeter scales. We find that the frequency shift of the quartz crystal microbalance is predominantly attributed to viscous effects in the lower mass range (below 1 mug/cm(2) copper electrodeposition) and only becomes representative of the added rigid mass in the higher mass range. We observe that the sensitivity of surface acoustic wave Love-mode devices appears constant over the whole mass range analyzed (0.5-10 mug/cm(2)), indicating a rigid layer interaction leading to a frequency shift representative of the deposited mass. (C) 2003 American Vacuum Society.