Currently I’m developing a H2O2 biosensor based on CuO and about to measure its amperometric response towards H2O2 concentration. My questions are:
First, how should I prepare H2O2 stock solution? Should I prepare only one stock solution or various solutions at different concentrations?
Second, how should I add H2O2 stock solution to the buffer solution? Should I add a same aliquot for every step?
Let me take an example to make my questions clear. My electrochemical cell contains 30 ml of phosphate buffer solution. Is it true if I add 30 µl of 1M H2O2 so that I can get the current response for H2O2 concentration at 1mM? After that, I’ll continue to add 30 µl more of 1M H2O2 to get the current response at 2mM?
If anyone has a detailed procedure, please send me. I would appreciate a lot. Thank you very much.
Hello Bui Tan
What type of biosensor are you working with exactly?
Does it allows the production of H2O2 or is H2O2 the substrate of the biorecognition layer?
You can definitely detect H2O2 using amperometry as a transduction technique. Basically, H2O2 will get oxidized at the electrode surface.
Could you be more specific please ?
Best regards,
Dear Bui Tan ,
It is best to replace the solution each time and replace with a solution of differing concentrations, formed from a high concentration stock. In this case the electrodes in the system should be rinsed with the new concentration to remove residual solution. In this way, it is best to start at the lowest concentration and work towards the highest.
However, this may not always be possible. For example, if the electrodes are delicate and if there are only a few electrodes available for testing. If this is the case, it is best to create a very high concentration of stock H2O2 and make low volume additions to increase the concentration. Adding minimal volume id important as each addition will increase the final volume; possibly causing an issue for analysing the detectable range if the cell has a fixed volumetric capacity. Also, the change in volume for each addition means that the concentration must be calculated with the new volume each time.
If I understand your request, you are actively searching for a protocol on how to get an amperometric response from H2O2?
If so, I would advice you to build a glucose biosensor:
Article Chapter 3. Electrochemical glucose biosensors
You will need to immobilize glucose oxidase (GOx) onto the electrode surface (there are many ways to do that):
Article Biosensors Based on Immobilization of Biomolecules by Electr...
Article Biomolecule immobilization on electrode surfaces by entrapme...
then by adding glucose you will see an increase in the current response using chronoamperometry at 0.7 V (do not forget the stirring because you will work in a steady-state/stationary mode ).
A second choice would be to consume H2O2 by using horse radish peroxidase (HRP) and a chromophore like toluidine.
I hope this helps.
Best regards,
Marie B.
Here is an example of a characterisation study of a hydrogen peroxide biosensor from my old group.
http://eprints.maynoothuniversity.ie/8036/1/JL-Development-2007.pdf
I never worked with this sensor personally, but as you can see from the methods/Figure 3, adding in known aliquots of hydrogen peroxide solution as you suggest is indeed possible (and works). Our lab typically used a Hamilton syringe and would briefly stir using a magnetic bead in the bottom of the cell (using the quiescent steady-state period post-stirring for analysis of the current).
Changing the entire solution in the cell is best case in a perfect world but it is impractical, increases the chances of error, and of damaging the sensors if you are taking them in and out of cell.
Dear Bui Tan ,
Please, find the information in our paper:
Article Nanoparticles of Noble Metals as Effective Platforms for the...
Best regards.
Hello!
I'm trying to use amperometry to detect the flow of carboxyl functional groups in paper-based microfluidic devices.
How should I select suitable material for working, counter and reference electrodes?
Also, I can't understand the use of buffer solutions in amperometry.
I would be much grateful if someone could help me with this.
Thank you!
- Badges
- Science method
- Similar topics
- Methodology
- Crystallography
- X-ray Diffraction