ISSN 4391-3199
African Journal of Chemistry ISSN: 4391-3199 Vol. 3 (1), pp. 102-113, January, 2016. © International Scholars Journals
Full Length Research Paper
Potentiometric sensors for phenylureas based on their molecularly imprinted particles
Boutros M. El Batout1,2* and Ibrahim V. I. Youssef1
1Chemistry Department, College of Science, Qassim University, Buraidah 6644, KSA.
2Chemistry Department, Faculty of Science, Ain Shams University, Cairo, Egypt.
E-mail:[email protected]
Accepted 1 December, 2015
Abstract
A molecularly imprinted polymer (MIP), with special molecule recognition properties of different phenylurea herbicides namely liuron (LU), isoproturon (IPU), diuron (DU), fenuron (FU) and methiuron (MU), was prepared by thermal polymerization in which phenylureas acted as the template molecules, methacrylic acid (MAA) acted as the functional monomer and ethylene glycol dimethacrylate (EGDMA) acted as the crosslinker. A biomimetic potentiometric field monitoring device was developed for the assessment of these phenylurea herbicides based on these newly synthesized imprinted polymers. The sensing elements were fabricated by the inclusion of phenylurea imprinted polymers in polyvinyl chloride (PVC) matrix. The sensors showed a high selectivity and a sensitive response to the template in an aqueous system. Electrochemical evaluation of these sensors revealed near-Nernstian response with slopes of 66.1±0.5 (r2 = 0.998), 59.6±1.3 (r2 = 0.997), 62.3±0.6 (r2 = 0.998), 67.1±0.3 (r2 = 0.998) and 71.5.0±0.4 (r2 = 0.998) mV decade− 1 with a detection limit of 1.0 × 10-5, 7.1 × 10-6, 1.3 × 10-5, 1.8 × 10-5 and 1.6 × 10-5 mol L-1 with MIP/LU, MIP/IPU, MIP/DU, MIP/FU and MIP/MU membrane based sensors plasticized with DOP, respectively. The sensors were easily used in a double channel flow injection system and compared with a tubular detector. The method had the requisite accuracy, sensitivity and precision to assay phenylureas in water samples.
Key words: Phenylurea herbicides, potentiometric sensors, flow injection analysis (FIA), molecularly imprinted polymers.