Electrochemical behavior and quantification of acetaminophen and tyrosine at clay/activated carbon composite film modified glassy carbon electrode

A composite (namely Sa-AC) made of 2.5 % of mesoporous carbon and 97.5 % of natural Cameroonian clay was obtained using batch method. As revealed by XRD analysis, the clay within the composite retains its layer structure despite a slight decrease of interlayer space between clay sheets. The as-obtained composite has larger surface area (ca 111 m²/g) and high pore volume compared to the pristine clay (90 m²/g), which endowed the composite film modified glassy carbon electrode (GCE), designated as Sa-AC/GCE, with a large active surface area and fast electron transfer rate. In contrast to the bare and clay modified electrodes, the composite film modified GCE has (i) good electrocatalytic activity toward acetaminophen (Acet) and Tyrosine (Tyr) via an EC mechanism, and (ii) the reversibility of the electrooxidation of Acet was not affected by the irreversible oxidation of Tyr. Under optimal conditions, and using linear sweep voltammetry, the composite film electrodes were used to simultaneously quantify Acet and Tyr in the range of 0.2 μM to 90 μM for Acet and 0.2 μM to 32 μM for Tyr with LOD of 0.19 μM and 0.23 μM (S/N = 3); LOQ of 0.77 μM and 2.05 μM (LOD = 10 S/M), respectively. The sensitivity of Sa-AC/GCE was estimated to be 0.022 μA/μM for Acet and 0.017 μA/μM for Tyr. In addition, the Sa-AC/GCEs were successful for the quantification of Acet in pharmaceutical medicine and Tyr in a tap water with a good recovery range from 91.30 to 109.44 % for the tablets and 102.47 % for tab water.