Disposable Screen Printed Carbon Electrode Based Electrochemical Sensors for the Determination of Brucine Chloramphenicol Niclosamide and Nicotine
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Date
2021-09-23
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Addis Ababa University
Abstract
In this study, various types of simple, scalable and low cost chemically modified electrodes were successfully developed for the sensitive and selective determination of niclosamide (NA), chloramphenicol (CAP), Nicotine (NIC) and Brucine (BRU). First, a simple and fast efficient activation of pristine bare screen printed carbon electrode (SPCE) was performed by linear sweep voltammetry using KOH solution and was used for the determination of NA and CAP. The activated-SPCE was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), electroactive surface area (ESA), Fourier transform infrared spectrometry (FTIR) and scanning electron microscope (SEM). The cyclic and square wave voltammetric (SWV) studies of NA in 30% DMF Britton-Robinson buffer (BRB) solution pH of 7.5 showed an electrocatalytic effects towards NA, which resulted in a higher current response and a negative shift in the peak potential at the activated-SPCE compared to the bare SPCE. Under the optimized conditions, a linear calibration curve was obtained using SWV in the range of 0.06 to 50 μM with a limit of detection and a limit of quantification of 0.0051 μM and 0.017 μM, respectively. Next, the same electrode material was used for the determination of CAP using SWV. The CV and SWV studies of CAP in 0.10 M phosphate buffer solution (PBS) pH 6.5 showed an electrocatalytic effect towards CAP, which resulted in a higher current response and a negative shift in the peak potential. The activated-electrode exhibited linear SWV responses towards the determination of CAP in the range of 0.05-100 μM with a limit of detection and a limit of quantification 0.02 and 0.067 μM, respectively. To the activated-SPCE, para-aminobenzene sulfonic acid (p-ABSA) was grafted electrochemically and SEM, EIS, CV, FTIR, and ultraviolet–visible spectroscopy (UV-Vis) were used for the characterization of the electrografted SPCE. The CV and EIS studies of the modified electrode showed that it has lower conductivity however; the grafted electrode has better electrocatalytic performance towards nicotine determination in BRB solution pH 8.0. The p-ABSA grafted SPCE exhibited excellent SWV responses towards NIC determination in the linear range of 0.5-300 μM with a limit of detection and a limit of quantification of 0.35 μM and 1.14 μM, respectively. Lastly, a new SPCE was prepared by electropolymerization of 3,4-Ethylenedioxythiophene (EDOT) on the surface of the p-ABSA grafted SPCE. The electrode was characterized by SEM, CV, ESA, EIS, FTIR and UV-Vis, and the formation of a highly conductive surface was confirmed by CV, ESA and EIS
studies. The polymer film modified SPCE was used for the determination of brucine (BRU). A significant enhancement in the peak current response for BRU was observed at the modified electrode compared to the unmodified electrode. The modified electrode demonstrated excellent SWV responses for the determination of BRU in the linear range of 0.03-5.0 μM with a limit of detection and a limit of quantification 0.012 μM and 0.042 μM, respectively. Generally, all the developed sensors were validated successfully for real sample analysis in pharmaceutical formulation and human urine samples with good recovery results. The proposed sensors also displayed good repeatability, reproducibility, long-term stability and selectivity towards potential interferents and are promising materials for the electrochemical sensing of these compounds in real samples.
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Keywords
Disposable Screen, Printed Carbon Electrode, Based Electrochemical, Determination, Niclosamide and Nicotine, Brucine, Chloramphenicol