Local concentration distributions within microstructures, alloy composition, the effects of side reactions and the influence of convection on electrodeposition in microstructures were measured. Since technically relevant microstructures have complex geometries, experiments involving locally resolved measurements using freely positionable microelectrodes are necessary. The SLCP method is based upon chronoamperometry and was used for simultaneous measurement of absolute concentration values of copper and nickel. In this way concentration profiles were measured as c(xy), c(x) and c(z). In a trench microstructure, concentration distribution was investigated as a function of the aspect ratio in unstirred solution and under convectional influence. In direct comparison to the conditions in the unstirred electrolyte, a notable intrusion of the flow is observed at aspect ratios less than or equal to 1. At a higher aspect ratio the concentration distribution is uniform. With higher aspect ratios leg 1.5) the effects of side reactions on the metal deposition increase. During Cu-Ni alloy deposition the formation of nickel oxide and nickel hydroxide layers can be detected.