Cyclic voltammetry (CV) was performed in 10 mM ferrocenecarboxylic acid (FCA) in 10 mM phosphate buffered saline (PBS) in the voltage range 0 -0 .6 V @ 100 mV s -1 using a commercial Ag/AgCl (Alvateck) external reference electrode. CVs were also undertaken in Ethidium bromide solutions in the voltage range 0 to -0 .6 V @ 100 mV s -1 using the on-chip platinum pseudo-reference electrode. A Square wave voltammetry protocol for detection of Ethidium bromide was developed with the conditions 22 mV/s and 10 mV amplitude versus the platinum on-chip reference electrode.