Development of a Perchlorate Chemical Sensor Based on Magnetic Nanoparticles and Silicon Nitride Capacitive Transducer

© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim We report in this work the development of a novel capacitance electrochemical sensors based on silicon nitride substrate (Si3N4) chemically modified with a structure of Cobalt phthalocyanine, C,C,C,C-tetracarboxylic acid-Polyacrylamide (Co(II)Pc-PAA). This sensitive layer was tested with and without magnetic nanoparticles (MNP) for perchlorate (ClO4-) detection. The developed chemical sensor with Si3N4/APTES-MNP/Co(II)Pc-PAA structure has shown a better performance when compared to the other structure based on Si3N4/Co(II)Pc-PAA. Contact angle measurements (CAM) and atomic force microscopy (AFM) characterizations have been performed to characterize the functionalization of the chemical sensors surface. Under the optimized structure of the chemical sensor, electrochemical measurements were carried out using Mott-Schottky analysis for ClO4- detection within the large range of 10−10 to 10−4 M with a very low detection limit of 2×10−10 M. The chemical sensor has demonstrated a high selectivity toward ClO4- when compared to other interfering anions such as Cl−, SO42−, and CO32−. The present capacitive chemical sensor is very promising for sensitive and rapid detection of ClO4- for environmental applications.