Cheapstat Lead determination

DkFran

I am trying to determine the lead in the water using the stripping voltammetry (constant voltage mode for the preconcentration + LSV for extraction), but I can not get good results, could someone perform similar tests with success or some reference of a journal using cheapstat for heavy metal detection? thanks

Jo

Hi @DkFran,
I haven't used the Cheapstat for lead metal measurements. Perhaps someone here will be able to answer that part of your question.
However, I have used the Rodeostat with square wave anodic stripping voltammetry. I have written two blog posts which describe these experiments:

PJS

Which electrodes are you using, which parameters for your scan, what's the limit of detection you are trying to reach?

I am planning to eventually use the Cheapstat for field analysis of Zn, Pb, Cu and Cd but for now we develop the methods with a better potentiostat. I'll try to report here when I have some results.

DkFran

Hi @Jo
Thanks for sharing the experiments with the RodeoStat, I think it is a very good alternative, however I try to do something similar to what is proposed there. I am currently doing IoT based on the CheapStat, I had difficulties in the electrochemical sensing part.

DkFran

Hi @PJS

Im using a glassy carbon working electrode, Ag/AgCl reference electrodes, and a graphite as a auxiliar electrode. For preconcentration i use ConstantVoltage (-400mV, 45 sec) and for stripping i use LSV -(start:-1000mV, Stop:-100mV , slope:20 mV/sec). I'm trying to determinate lead between 10 ppm and 50 ppm. I would really appreciate it if you could show your results with the parameters you use.

PJS

Hi @DkFran

At this concentrations, it should not be too much of a problem to measure Pb, even though GC electrodes are not very sensitive. Is -400mV a low enough potential to accumulate Pb onto the electrode ? Have you tried at -0.8V?
Also, I don't know if there is Cu in your solution but I remember having some disappearance of the Pb signal with addition of Cu.

If it doesn't work, maybe try a gold electrode which is a bit more sensitive to Pb. Or maybe modify your GC electrode by depositing some bismuth on the surface.

Good luck!