A Chitosan/TiO2 Nanoparticles-Entrapped Carbon Paste Electrode Covered With dsDNA as a New Electrochemical Biosensor for the Determination of Acetaminophen

A rapid, sensitive and inexpensive method was proposed for electrochemical determination of acetaminophen (ACT) using a carbon paste electrode modified with chitosan/TiO2 nanoparticles covered with double-stranded deoxyribonucleic acid (dsDNA) as working electrode. Interaction between the ACT and immobilized dsDNA accumulates ACT on the electrode surface. Differential pulse voltammogram was recorded using pulse amplitude of 0.05 V and scan rate of 25 mV/s. A peak current related to the concentration of ACT at about 550 mV was taken as an analytical signal. The effects of different experimental parameters on the oxidation current of the ACT were studied and optimized. The electrochemical signal was found to be linear in the concentration range of 0.50- $35.0\mu \text{M}$ and 35.0- $300.0\mu \text{M}$ with a detection limit of $0.14\mu \text{M}$ . In addition, the values of RSD% for the determination of ACT at $20\mu \text{M}$ and $155\mu \text{M}$ were calculated to be 2.75% and 1.56%, respectively ( $n=5$ ). The accuracy of the proposed technique was evaluated by the determination of ACT in a 325-mg ACT tablet. The applicability of the method was successfully extended to the determination of ACT in serum and pill sample.