Creating a baseline in CH Instruments (model CHI 1000C electrochemical station)

[Nick Radek]

Good afternoon, dear experts in electrochemistry, I have a question. I recently started learning about the CHI₁₀₀₀C electrochemical station and electrochemistry in general, as I need to know it for my scientific work. I want to build a calibration line, however I don't know how to make a baseline in CH Instruments to accurately determine the current. I have 6 sweeps, and I want to find out exactly what the current will be through the Gaussian peak and the baseline superimposed on it. However, I am unable to do this. The current is usually determined through the baseline, but even when you configure the Gaussian peak in the settings, the program does not build either a baseline or determine the peak. Has anyone worked in the program and knows how to do this in the program? The options to do this in Excel and Origin are not suitable, I can already do it in these programs, but it takes a very long time, and since I am newcomer to electrochemistry, I would really like to be able to learn this faster and more accurately. Moreover, sometimes if I got two peaks, anodic and cathodic, the programm can define only one peak but don't define another I'll post here a photo of the peak that I would like to process in the program so that you understand what I want to do. Thanks in advance for your understanding.

[ChenBeier]

It looks like a cyclovoltagramm of a CVS Analysis.
The base line is at 0 mA. To see more clear the curve it's put down to - 2,7 mA. Isn't it. But this should be changed in a setting of the plotting. Refer to the manual to your device.

The start is at about -0.05 V. voltage is increased to + 0.422 V were the peak 1,4 mA occurs. Further increases to 1.5 V shows the rest of the curve. At 1.5 V the voltage will be decreased and the back sweat occurs which ends at the start point -0.05 V

https://www.chinstruments.com/chi1000.shtml

[Nick Radek]

So will this correction help me to build the baseline? What to do exactly using manual?

[Nick Radek]

Good evening, I have a question. Should the calibration of solutions in cyclic voltammetry generally be linear? I tried to build a calibration line using solutions of CuSO₄*5H₂O and NiSO₄*6H₂O, but a straight line did not work out. Until now, I had never been strict with this method of analysis and was already accustomed to the fact that in other methods of analysis - chromatography, photometry, spectrometry, I was able to achieve direct calibration. But here it doesn’t. Where the concentration is twice as high, it does not turn out to be 2 times more. The GPT chat showed a lie that a straight line would not work. What is necessary when constructing a gradation? Should I make every point on the graph in three parallels? I can’t calibrate a device that was placed in a new playing place at all, can I? Can you advise me something?

[ChenBeier]

Describe what you realy want to do. CVS normally detect redox pairs.
Coppersulfate or nickelsulfate has only Cu₂+ + 2 e-=> Cu or Ni₂+ + 2 e- => Ni.
These reductions can be destirbed by other components in the solution. So there are additives in plating Bathes for brightnes and levelling, which accelate or inhibit the reaction, this can be detected by CVS. But I dort know what you mean to make a baseline with a metal salt.

[Nick Radek]

I recently moved the device to another location. I need to calibrate it, for this I have prepared standard solutions of various concentrations of copper sulfate. And I want to build a calibration line according to these standards. I expected that the current peak would increase in proportion to the concentration, but this does not happen either.

Postscript: I used to do spectrometry and chromatography, where the baseline is the background line, relative to which the concentration of a substance is calculated by height (half-height) or peak area

[ChenBeier]

The peak is not related to the concentration of the Copper.
The peak is related to the force what is need to deposit or strip the metal.
You cannot measure the content of copper by CVS.
You can measure a inhibitor or accelartor by changing the plating behaviour.

[Nick Radek]

Ok, now I see, thank you, could you recommend to me several ways of how to check the electrochemical station (potetiostat) performance?

[fizzlewage]

Start by running a calibration with a standard solution, such as ferricyanide, to verify accuracy. Conduct an impedance test on a dummy cell to confirm correct frequency response, and measure open-circuit potential (OCP) stability to check drift. Additionally, run cyclic voltammetry and ensure that the peak shapes and positions are consistent with expected results. Lastly, review the stability of current responses to detect any noise or drift in the readings.