Reactive oxygen and nitrogen species (ROS/RNS) such as hydrogen peroxide (H2O2) are typical byproducts of oxygen metabolism and can lead to oxidative stress when produced in large amounts. This is a concern since oxidative stress can cause neurodegenerative diseases such as Alzheimer’s, Parkinson’s, and some forms of cancer. While there are several modes of detection of ROS/RNS like H2O2, electrochemical methods offer several advantages: low cost, capability to be miniaturized, and rapid detection. With respect to the electrodes, carbon-based materials are particularly useful due to their ability to be adapted to different measurement scenarios. For H2O2, carbon-fiber microelectrodes are most common but tend to foul with long-term exposure to an oxidative environment. Boron-doped diamond (BDD) can mitigate this issue due to its general robustness; it also exhibits a small capacitive current, enhanced surface roughness, and a large potential window. BDD can also be modified to increase sensitivity towards a specific analyte, like H2O2. In this work, we performed a comprehensive study of BDD electrodes modified with silver (Ag), gold (Au), palladium (Pd), and platinum (Pt) nanoparticles for the detection of H2O2. The modification involves a 2-step wet chemical synthesis procedure directly onto the electrode surface. Several factors were investigated including the double-layer capacitance, electroactive surface area, electron transfer properties, and sensitivity to H2O2, among others. It was found that the modification yielded a 1x (Ag), 1.1x (Au), 178x (Pt), and 184x (Pd) increase in sensitivity compared to the bare BDD electrode. The best combination of analytical figures of merit was observed with Pd where the limit of detection (LOD) was calculated to be 20 µM. The H2O2 measurements also exhibited excellent repeatability as the relative standard deviation (%RSD) was below 10% for all modifications. In general, this work further exemplifies the versatility of diamond electrode for detection of bioanalytes.

Comparisons of metal nano-particle modified boron doped diamond electrodes for the electrochemical detection of hydrogen peroxide

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.