Development and application of electrochemical sensors using conductive ink with carbon black and shellac for the detection of Paraquat

In the search for new electrochemical sensors with disposable potential, screen printing technology has gained notoriety due to its advantages such as high sensitivity and relatively low. Paraquat is a pesticide for weed control used in many crops. However, it is a highly toxic substance that can cause severe damage to the lungs, kidneys and other organs and is potentially fatal if ingested. Considering that paraquat has toxic effects, the development of sensors that can detect the presence of this substance is a viable solution in this context. In this context, a conductive ink based on carbon black, purified shellac and glycerol has been developed in the present work. The system consists of two working electrodes, a pseudo reference electrode and a counter electrode. Scanning electron microscopy and X-Ray diffraction were used for the morphological and structural characterization. For electrochemical characterization, cyclic voltammetry was performed with 1.0 mmol L^-1 FcMeOH in 0.1 mol L^-1 KCl. Using square wave voltammetry (SWV) scanning in the window -1.5 to 0, we obtained two oxidation peaks of the analyte at approximately -1.1 V and -0.7 V, with peak currents of 3.1 µA and 7.0 µA, respectively. Using the SWV in the window 0 to -1.5 we obtained two reduction peaks of the analyte at approximately -1.0 V and -0.6 V, with peak currents of -2.1 µA and -8.0 µA, respectively. In conclusion, the new conductive ink is an interesting alternative for constructing electrochemical sensors that can be used for PQ detection.