Microporous carbon in the selective electro-oxidation of molecular biomarkers: uric acid, ascorbic acid, and dopamine

Abstract

Herein, we demonstrate the superior electrocatalytic activities of microporous carbon in the oxidation of three molecular biomarkers, ascorbic acid (AA), dopamine (DA), and uric acid (UA), which are co-present in biological fluids. The voltammetric responses of AA, DA, and UA at the low-cost microporous carbon electrode show significantly better sensitivity and selectivity than other more expensive and commonly used electrode materials such as copper(II) oxide, copper(I) oxide, and carbon nanotube. Differential pulse voltammetry at the microporous carbon electrode allows the detection of AA, DA, and UA with linear ranges of 100–2000 μM (AA), 10–150 μM (DA), and 10–150 μM (UA), sensitivities of 6.8 ± 0.2 nA μM⁻¹ (AA), 261.4 ± 3.4 nA μM⁻¹ (DA), and 93.5 ± 2.0 nA μM⁻¹ (UA), and detection limits of 23.1 μM (AA), 0.2 μM (DA), and 1.7 μM (UA). The method has been validated with a synthetic urine sample to yield ∼100% recoveries for all three analytes. The developed method has been further applied in the investigation of the peroxide scavenging activity of UA.