this work describes the construction and characterization of an electrochemical flow-through microcell with the three electrodes (working, pseudo-reference, and auxiliary) inserted in microchannels with thickness smaller than 20 μm. these microchannels were constructed between two stacked polycarbonate slides using one or more overlapped toner masks as spacer. this strategy allows the construction of microcells with a variable internal volume on the working electrode (0.6 to 2.4 μl). three different materials were optimized as electrodes: gold film or graphite-epoxy composite as working electrode, silver-epoxy composite as pseudo-reference electrode and, graphite-epoxy composite as auxiliary electrode. the performance of the microfluidic cell was characterized by cyclic voltammetry, potentiometric stripping analysis at constant current, and square wave anodic stripping voltammetry using ferrocyanide and heavy metals (cu2+, hg2+, pb2+, and cd2+) as model analytes.