Co-detection of neurotoxic heavy metals using modified multi-bore carbon fiber microelectrodes via fast-scan cyclic voltammetry

Noel Manring, Miriam Strini, Gene Koifman, Jonathan Xavier, Pavithra Pathirathna

Department of Chemistry and Chemical Engineering , Florida Institute of Technology, Melbourne, FL

Neurotoxic heavy metals, such as Cd(II) and As(III), have gained considerable concern due to high global contamination rates from drinking water. Once these neurotoxic agents enter the human body, they permeate the blood-brain barrier, causing extensive and often irreversible damage to the central nervous system in addition to other vital organs. Therefore, developing an ultra-sensitive and timely detection method for these toxic heavy metals is critical. Traditionally employed metal detection methods require extracting a biological sample from the body; thus, altering metal speciation, a crucial factor in determining toxicity. Furthermore, these methods of analysis are not translatable to living systems. In this study, we first electrodeposited carbon fiber microelectrodes (CFMs) with gold nanoparticles (Au NPs) to optimize detection parameters for Cd(II) via fast-scan cyclic voltammetry (FSCV).  We then performed an in-depth pH study to optimize the electrochemical parameters for As(III) detection due to its complex aqueous chemistry. We constructed calibration curves for both analytes in tris buffer that mimics artificial cerebellum fluid to obtain excellent detection limits (LOD). Additionally, we conducted selectivity studies and found that our optimized waveforms are specific to Cd(II) and As(III), respectively. In our final study, we fabricated a double-bore CFM with Au NPs on one singular CFM to successfully co-detect Cd(II) and As(III) simultaneously. To the best of our knowledge, this is the first report of the use of CFMs, both single and double-bore, modified with Au NPs for the electrochemical detection of Cd(II) and As(III) via FSCV.