What kind of metal (alloys) you investigate???

Keep your reference electrode close to your working electrode, you can reduce the Rs.

Keep your reference electrode close to your working electrode, you can reduce the phenomenon of the Rs .

Dear Ogunmolasuyi Adewoyin,

electrode's corrosion[1,2] and the following possible dissolution[1] processes of some (partially or completely[3] ionized oxides/Hydroxides) dissociates from the barriers might affect (as an "aging" process) your solution resistance (so that your Rs, "becoming big"). Also, measure a possible drift in pH values, due to the (proposal of the) electrode's  corrosion.

1.  EIS characterization of a Ti-dental implant in artificial saliva media: dissolution process of the oxide barrier   http://www.sciencedirect.com/science/article/pii/S002207280400049X

2. https://www.researchgate.net/publication/274631346_Corrosion_resistance_of_Ti_and_Ti-Pd_alloy_in_phosphate_buffered_saline_solution_with_and_without_H2O2_add

3. Tables of Strong Acids and Bases   http://www.chemistry.pomona.edu/chemistry/1alab/www/fall2006/powerptpresentations/5anions/acidbaset.htm

Article Corrosion resistance of Ti and Ti-Pd alloy in phosphate buff...

Thank you very much. I am using gold electrode

Rs it is resistance of electrolyte but also Rs can consist for example resistance of  any layer which exist on electrode surface, gas bubles electrochemical reactions. Evryone are  right. :)

Thank you very much

Dear Ogunmolasuyi Adewoyin,

ok, you are using gold electrode, as a WE. What are the other(s) (CE and/or RE) electrode(s) ?

Dear Ogunmolasuyi Adewoyin,

could You present Your electric circuit with explanation of each element?