A Novel Label-Free Immunosensor Based on Activated Graphene Oxide for Acetaminophen Detection

A simple label-free immunosensor for the selective detection of acetaminophen was developed by modifying a graphite based screen-printed electrode with graphene oxide after the functionalization with N-hydroxysuccinimide in the presence of 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride. The template made by layer-by-layer technique provides activated carboxylic groups, which form amidic covalent bonds with the terminal amine groups from the antiacetaminophen antibody. The optimization of antibody immobilization and the blocking of the free active groups from graphene template with bovine serum albumin was performed by using electrochemical impedance spectroscopy, cyclic voltammetry and square wave voltammetry. The electrochemical quartz crystal microbalance technique was used to determine the quantity of different components deposited onto the electrode surface during the optimization steps. The above described immunosensor was applied with good results for the determination of acetaminophen in synthetic and real samples by using square wave voltammetry. A limit of detection of 0.17 mu M (S/N=3) was obtained with no or minimal interference of dosage forms excipients and serum components.