Preparation of Fe3O4@silica sulfuric acid/MWCNT-modified electrode for detection of acetaminophen in the presence of ascorbic acid

Acetaminophen (AC) and Ascorbic acid (AA) plays an important role in human health. At traditional electrodes, AC is oxidized at potentials close to that of AA, resulting in an overlapping voltammetric response. In this work, a carbon paste electrode (CPE) is modified by incorporating Fe3O4@silica sulfuric acid/multi-walled carbon nanotubes (MWCNT). The resulted modified electrode is used as a sensitive voltammetric sensor for simultaneous determination AA and AC. The electrode showed efficient electrocatalytic activity in lowering the anodic overpotentials and enhancement of the anodic currents. This electrode is able to completely resolve the voltammetric responses of AA and AC. The effects of potential sweep rate and pH of the buffer solution on the response of the electrode, toward AA and AC, and the peak resolution is thoroughly investigated by cyclic and differential pulse voltammetry (CV and DPV).The best peak resolution for these compounds using the modified electrode is obtained in solutions with pH 4.0. Peak potential separation nearly 350 mV is resulted for two compounds. The modified electrode showed good sensitivity and selectivity. The electrode has very good reproducibility (R.S.D.≤3%), high stability in its voltammetric response (more than two months without any considerable change in response) and low detection limit (0.8 μM) for both AA and AC. The prepared electrode is successfully applied for the voltammetric detection of AA and AC in pharmaceutical preparations.