Simultaneous Analysis of Ascorbic Acid, Uric Acid, and Dopamine at Bare Polystyrene Thermoplastic Electrodes

Abstract

Simultaneous analysis of ascorbic acid (AA), uric acid (UA), and dopamine (DA) is desirable as they are important biomarkers that coexist in biological fluids. Electrochemical detection of these molecules can be challenging as their oxidation peaks are poorly resolved at most unmodified electrodes. Modifications are typically necessary for analysis which increase cost and complicate fabrication. Herein, inexpensive and moldable polystyrene thermoplastic electrodes (PS TPEs), that can be used for simultaneous analysis of AA, DA, and UA, without surface modification, were presented. Electrode composition was optimized for conductivity, capacitance, and electrochemistry. Detection limits were 4, 0.9, and 4 μm for AA, DA and UA respectively. PS TPEs were also challenged in urine; excellent recoveries (90-110 %) were seen for AA and UA. DA showed lower recoveries (82 % for 10 μm and 47 % for 5 μm), but in the future, higher recoveries can be achieved through design considerations and further material optimization.

Surface Modification of Thermoplastic Electrodes for Biosensing Applications via Copper-Catalyzed Click Chemistry

“…Thermoplastic electrodes (TPEs) made of TC303 carbon (Asbury Graphite Mills Inc., NJ) and 45,000 MW polystyrene (Sigma-Aldrich, St. Louis, MO) in poly­(methyl methacrylate) (PMMA) templates were fabricated as previously reported. , They were prepared for each experiment by wet sanding for 30 s each in a figure-eight pattern on silicon carbide sandpaper at 150 and then 600 grit. They were then sonicated in ultrapure water for 5 min and air-dried before use.…”

“…Thermoplastic electrodes (TPEs) have been shown to have a wide range of applications including ion-selective electrodes, Escherichia coli sensors, and enzymatic glucose sensors. − The advantage of using these carbon composite electrodes is they are robust and yield better electrochemistry than other carbon electrodes, such as screen printed carbon electrodes (SPCEs), while being less expensive than traditional precious metal electrodes . However, there is a gap in the ability to modify TPEs consistently and reliably for biosensing applications, particularly for the immobilization of biorecognition elements such as antibodies and aptamers.…”

Characterization of Factors Affecting Stripping Voltammetry on Thermoplastic Electrodes

“…They are easily fabricated carbon composite electrodes that maintain exceptional conductivity and electron transfer kinetics. [13][14][15][16][17][18][19][20] Three primary thermoplastic binders have been explored for TPEs, including polymethyl methacrylate (PMMA), 13,21 polycaprolactone (PCL), 14,16 and polystyrene (PS). 17,18 All binders create functional electrodes, but their individual properties greatly influence their application due to their unique surface and electrochemical properties.…”

“…[13][14][15][16][17][18][19][20] Three primary thermoplastic binders have been explored for TPEs, including polymethyl methacrylate (PMMA), 13,21 polycaprolactone (PCL), 14,16 and polystyrene (PS). 17,18 All binders create functional electrodes, but their individual properties greatly influence their application due to their unique surface and electrochemical properties. The type of carbon used has also been examined, including a variety of sized particles from 500 nm to 130 μm of naturally and synthetically sourced graphite.…”