I am currently studying the detection of Pb and Cd using SPGE. The following parameters have been used i.e. deposition potential of -1.4 V, deposition time of 200 s, step increment of 5 mV, pulse amplitude of 50 mV, pulse frequency of 25 Hz, electrolyte 0.1 M acetate buffer, pH 4.5. I found out that the shape of peaks for target heavy metals of the same concentration kept fluctuating. I think it was due to the presence of remaining heavy metals on the surface of the electrode after the stripping step. I have tried to LSV at a potential range of (-1.2 V to -0.2 V) but the peak shape was still fluctuating. Hence, I would like to ask whether there are any suggestions for the cleaning of heavy metals from the surface of the electrode.