Electrochemical Determination of Acetaminophen by a Glassy Carbon Electrode Modified with Over-Oxidized Poly ۴-Aminophenol

Contamination of the environment is an important issue that can influence the human being health and the life quality. One of the new emerging contaminants s is acetaminophen, that is widely used as a painkiller, analgesic, and antipyretic medicine globally. It was reported that ۵۸–۶۸% of acetaminophen is excreted by human urine and it is also prone to bioaccumulation in aquatic organisms. In this regard, a novel electrochemical sensor based on over-oxidized poly ۴-aminophenol was fabricated for determination of trace amounts of acetaminophen. ۴-aminophenol was polymerized electrochemically on the surface of glassy carbon electrode (GCE) by cyclic voltammetry method and then overoxidized by applying constant potential (+۱.۲ V (vs SCE)) in order to increase its conductivity, porosity and electrocatalytic activity. Subsequently, the modified GCE was employed for anodic stripping square wave voltammetric determination of acetaminophen. Square wave voltammograms of acetaminophen solutions using the modified GCE showed a well-defined peak at +۰.۶۳ V (vs SCE). In order to achieve the highest sensitivity, all of the operational and instrumental parameters including pH, nature of supporting electrolyte, accumulation time, accumulation potential, frequency, pulse amplitude and voltage step were optimized. The results showed that the maximum peak current with normal shape could be obtained at pH=۲, KNO۳ ۰.۱ M (as the supporting electrolyte), ۶۰ S (accumulation time), ۰.۰۵۵ V (accumulation potential), ۷۵ Hz (frequency), ۵۰ mV (pulse amplitude) and ۱۰ mV (voltage step). Under the optimum conditions, the proposed sensor showed a wide linear range over the concentration range of ۰.۳-۱۰۰ μM with a correlation coefficient of ۰.۹۹۴۹. The reproducibility of the designed sensor was also evaluated for five replications (۱۰ μM solution of acetaminophen) and the %RSD value was and %۳.۲. The limit of detection (LOD) and limit of quantitation (LOQ) values of the developed sensor were ۰.۰۷ μM and ۰.۲۳ μM respectively.

کلیدواژه ها:

Acetaminophen ، Square wave voltammetry ، Glassy carbon electrode ، Electrochemical sensor