How to Improve the Sensitivity Measurement of a Chemical Sensor?

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SUMMARY

The discussion focuses on improving the sensitivity measurement of a chemical sensor using chronoamperometry. The user, engineman, is testing the sensor's response to K3Fe(CN)6 and Ascorbic Acid with a Gamry FAS1 Potentiostat setup. Despite a successful cyclic voltammetry (CV) scan, the chronoamperometry experiment yielded only noise, prompting inquiries about potential issues such as the concentration of KCl and the applied potential during measurements. Engineman seeks advice from others with experience in similar experiments.

PREREQUISITES
  • Understanding of chronoamperometry techniques
  • Familiarity with cyclic voltammetry (CV) methods
  • Knowledge of potentiostat operation, specifically the Gamry FAS1
  • Basic chemistry concepts related to K3Fe(CN)6 and Ascorbic Acid
NEXT STEPS
  • Research optimal settings for chronoamperometry, including potential adjustments
  • Investigate the effects of KCl concentration on electrochemical measurements
  • Explore noise reduction techniques in electrochemical data collection
  • Learn about alternative methods for measuring chemical sensor sensitivity
USEFUL FOR

Chemical engineers, electrochemists, and researchers developing chemical sensors who are looking to enhance measurement accuracy and sensitivity in their experiments.

engineman
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I am developing a new chemical sensor. I want to test the sensitivity of the sensor to various chemicals such as K3Fe(CN)6 and Ascorbic Acid. My understanding was that you could use a chronoamperometry scan to do this measurement by injecting a controlled amount of chemical every 60 seconds and recording the increase in steady state current observed after 15-20 seconds. This gives a stair step looking graph when the data is plotted. However, when I tried the experiment tonight, I couldn't get any meaningful data. All I could see in the data was noise. Here is my setup:

Gamry FAS1 Potentiostat
Pt wire Aux Electrode
Orion Single Junction Ag/AgCl Reference electrode
Pt disc electrode

I was trying to measure K3Fe(CN)6 in 0.1M KCl. The K3Fe(CN)6 concentrations increased from 1uM to 10mM logarithmically. I can get a good result with a CV scan so I know that the system is connected properly and working well.

Does anyone have experience with performing an experiment like this? Is my concentration of KCl too high. Does anyone have any other suggestions.

Thanks,
engineman
 
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What did you have your potential set to? Hopefully it was set to a potential of one of the peaks on your CV...
 

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