ZP answers technical questions that have come in, please return to this page after the 20 April 2025.
QUESTION ONE – Custom electrodes for Aflatoxins
The discussion revolves around aflatoxin sensors, specifically whether to use gold or carbon-based electrodes. The key points are:
- Gold is not ideal for aflatoxin sensors due to high cost and unsuitability for the low-margin food industry. The price of gold has tripled over the past decade and is expected to rise further.
- Carbon is a better alternative, being much more affordable while still viable for biosensors.
- Customization isn’t practical for small-scale production (1,000 units isn’t enough for true manufacturing). The cost and complexity of customization outweigh the benefits.
- Existing designs work well—standard screen-printed electrodes and commercial platforms like Sense It All provide well-thought-out, easy-to-handle solutions.
- Hand-build and test before considering customization. A thousand sensors should be tested manually before scaling up manufacturing.
QUESTION TWO – Trouble shoot ZP Carbon 501 screen printed electrode.
In this video, I tackle a user’s issue with distorted cyclic voltammograms obtained using ZP 501 carbon screen-printed electrodes and a ferricyanide solution. The user was seeing some distortion in their voltammogram We first considered connection problems, which is always a good place to start. However, after reviewing their setup and results, I suspected a more fundamental issue: the working and counter electrodes might be connected in reverse. The user’s current readings were four times higher than expected, which strongly suggested a larger electrode area was inadvertently acting as the working electrode. This incorrect setup would inevitably lead to a higher IR drop, directly causing the observed distortions. To demonstrate this I replicated the user’s experiment with the correct connections. As you can see in the results, the current is much lower, and the voltammogram looks as expected. So, the most likely culprit? Reversed electrode connections. While minor factors like chloride concentrations and the connector’s quality could play a small role, the reversed electrodes seem to be the primary cause of the distorted data. Hopefully, this clarifies things for the user.