(295l) A Novel, Ultra-Fast Electrochemical Detection of Neurotoxic Cadmium and Arsenic Using Carbon Fiber Microelectrodes and Fast-Scan Cyclic Voltammetry

Neurotoxic agents like Cd(II) and As(III) pose a significant global health risk, especially through contamination of drinking water. Prolonged exposure to these toxins via water, food, and air can lead to various health complications, including cardiovascular diseases, neurological disorders, cancer, and even death. Hence, there's a critical need for highly sensitive and rapid detection methods to identify these heavy metals in biological systems. Traditional metal detection methods typically involve extracting samples from the body, which alters metal speciation, a key factor in determining toxicity. Moreover, these methods aren't suitable for real-time measurements in living organisms. While electrochemists have devised detection methods for neurotoxic agents, they often lack specificity regarding metal speciation and are primarily applicable to environmental samples, rendering them unsuitable for in vivo analysis. In our study, we've optimized fast-scan cyclic voltammetry (FSCV) to detect Cd(II) and As(III) using carbon fiber microelectrodes (CFMs) with a temporal resolution of 100 ms. We employed gold nanoparticles (Au NPs)-modified CFMs for Cd(II) detection and bare CFMs for As(III) detection. Characterization of both sensors was conducted in a tris buffer mimicking artificial cerebellum fluid. Calibration curves were established for both analytes to determine the limit of detection, linear range, and sensitivity. Additionally, comprehensive selectivity tests were performed in the presence of other interfering ions to assess sensor specificity. Furthermore, we conducted an in-depth pH study, particularly for As(III), given its complex aqueous chemistry dependent on medium pH. Our research demonstrates that Au NPs-modified CFMs can detect ultra-low concentrations of Cd(II) in artificial urine samples. Notably, this study marks the first instance of Cd(II) and As(III) detection under ambient conditions using FSCV and CFMs at ultra-fast temporal resolution. Our preliminary findings suggest promising prospects for utilizing these sensors in future in vivo applications, particularly within the brain.