Comparison of two fabricated aptasensors based on modified carbon paste/oleic acid and magnetic bar carbon paste/Fe3O4@oleic acid nanoparticle electrodes for tetracycline detection

Abstract

In this research, we have improved two aptasensors based on a modified carbon paste electrode (CPE) with oleic acid (OA), and a magnetic bar carbon paste electrode (MBCPE) with Fe3O4 magnetic nanoparticles and oleic acid (OA). After the immobilization process of anti-TET at the electrode surfaces, the aptasensors were named CPE/OA/anti-TET and MBCPE/Fe3O4NPs/OA/anti-TET respectively. In this paper, the detection of tetracycline is compared using CPE/OA/anti-TET and MBCPE/Fe3O4NPs/OA/anti-TET aptasensors. These modified electrodes were characterized by infrared spectroscopy (IR), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), UV–vis spectroscopy, and voltammetric methods. The linear range and the detection limit for TET with the CPE/OA/anti-TET aptasensor were found to be 1.0×10−12–1.0×10−7M and 3.0×10−13M respectively by EIS method. The linear range and the detection limit for TET with the CPE/OA/anti-TET aptasensor were found to be 1.0×10−10–1.0×10−7M with a limit of detection of 2.9×10−11M using differential pulse voltammetry (DPV) technique. The MBCPE/Fe3O4NPs/OA/anti-TET aptasensor was used for determination of TET, and a liner range of 1.0×10−14–1.0×10−6M with a detection limit of 3.8×10−15M was obtained by EIS method. Also, the linear range and detection limit of 1.0×10−12–1.0×10−6M and 3.1×10−13M respectively, were obtained for MBCPE/Fe3O4NPs/OA/anti-TET aptasensor using DPV. The proposed aptasensors were applied for determination of tetracycline in some real samples such as drug, milk, honey and blood serum samples.