Editors: | F. Kongoli, H. Inufasa, M. G. Boutelle , R. Compton, J.-M. Dubois, F. Murad |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2018 |
Pages: | 216 pages |
ISBN: | 978-1-987820-84-3 |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
4-Nitrophenol (4-NP) is a highly hazardous and toxic phenol, which can cause significant damages to the health and to the environment [1,2]. Thus, the interest in its determination in environmental samples has led to the development of several quantification methods. The present work describes the development of a highly sensitive and selective molecularly imprinted electrochemical sensor (MIS) for its detection. The MIS film was prepared in three steps. The first used vinyltrimethoxysilane-modified MWCNTs (MWCNTs-VTMS), a procedure adapted from Correa et al.[3]. Thereafter, VTMS and AIBN were added to the previous mixture (MWCNT- VTMS and DMF). The flask was placed in a thermal oil bath at 70°C, under stirring, for 48 hours. At the second step, for the preparation of the GCE modified with MWCNTs-VTMS, the resulting suspension was dropped onto the GCE surface, and allowed to dry, at room temperature. At last, the imprinted sensor was prepared using the acid catalyzed hydrolysis and condensation of tetraethoxysilane, phenyltriethoxysilane and 3-aminopropyltrimethoxysilane, in the presence of 4-NP as the template molecule and in its absence. For the characterization of the silanes' films, SEM, TGA and FTIR were used. The electrochemical performance of the imprinted siloxane film was characterized by cyclic voltammetry and differential pulse voltammetry. This sensor showed its best performance in 0.1 mol L-1 phosphate buffer solution, at pH 7.0. After optimizing the operational conditions, this sensor provided a linear response range for 4-NP from 0.1 up to 100 mol L-1 and good parameters as LOD (0.03 mol L-1), and sensitivity (1.4 x 10-2 A mol L-1). Furthermore, the MIS/4-NP sensor exhibited good stability with adequate reproducibility and accuracy.