Voltammetric determination of acetaminophen in the presence of NADH using ionic liquid /ZnO nanoparticle carbon paste electrode

Acetaminophen (AC) with an acetylated aromatic amide is the most widely used antipyretic and analgesic drug in the world. It is commonly used for the treatment of fever, minor aches and pains. However, many studies have shown that hypersensitivity or overdose in few cases leads tothe formation of some liver and nephrotoxic metabolites [1]. AC toxicity is highly dependent to the formation of the reactive metabolite, N-acetyl-p-benzoquinone imine (NABQI) [2,3]. On theother hand, studies show that Dihydronicotinamide adenine dinucleotide (NADH) efficiently reduces NAPQI to AC. By having enough NADH in the body, we can ensure that NAPQI levels will be kept low [4]. Thus, it is very important to create suitable conditions for the simultaneousanalysis of AC and NADH in biological samples such as urine and blood. In the present study a carbon paste electrode modified with ZnO nanoparticle (ZnO/NPs) and room-temperature ionic liquid (RTIL), 1-methyl-3-butylimidazolium chloride was fabricated. The direct electro-oxidationbehavior of acetaminophen (AC) was carefully studied by cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS). The results exhibitedremarkable increase in the electron transfer rate and significant decrease in the overpotential forAC oxidation reaction in contrast to that on the bare carbon paste electrode (CPE). The oxidation peak current was linearly dependent on AC concentration in the range of 0.1 – 550 μM with the detection limit of 0.07 μM, using square wave voltammetry (SWV). Synergistic effects in theenhanced signal were observed when both ZnO nanoparticles and ionic liquid were employed. The proposed sensor has been successfully applied for the determination of AC in urine, serum and pharmaceutical samples, demonstrating the feasibility and reliability of the proposed method.

Keywords:

Acetaminophen , Electrochemical sensor , Ionic liquid , Zinc oxide , Nanoparticle