DEVELOPMENT OF AN ELECTROCHEMICAL SENSOR MODIFIED WITH MWCNT-COOH AND MIP FOR DETECTION OF DIURON. (10th November 2015)

• Record Type: Journal Article
• Authors: Wong, Ademar; Foguel, Marcos Vinicius; Khan, Sabir; Oliveira, Fernanda Midori de; Tarley, César Ricardo Teixeira; Sotomayor, Maria D.P.T.
• Is Part Of: Electrochimica acta. Volume 182(2015)
• Page Start: 122
• Page End: 130
• Publication Date: 2015-11-10
• Subjects: Diuron -- electrochemical sensor -- adsorption -- molecularly imprinted polymer -- MWCNT-COOH; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2015.09.054
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: Sensitive and selective detection of diuron in environmental samples. Electrochemical sensor modified with MIP and MWCNT-COOH. Diuron herbicide can have important environmental impacts. Monitoring of diuron by HPLC and square wave voltammetry. MIP-based adsorbent material for monitoring purposes. Abstract: An electrochemical sensor modified with a molecularly imprinted polymer (MIP) and carboxyl-functionalized multi-walled carbon nanotubes (MWCNT-COOH) was developed for the sensitive and selective detection of diuron in river water samples. An MIP was obtained by bulk polymerization using the best monomer (methacrylic acid) selected by computational simulation. The surface characteristics of the MIP and NIP (control polymer) samples were evaluated by means of surface area and pore volume determinations, using the BET method. The adsorption efficiency of the MIP was determined in adsorption tests that revealed high adsorption, relative to the control polymer. In addition, MWCNTs functionalized with carboxyl groups were used to enhance the performance of the sensor. Electrochemical studies of diuron using the MIP and MWCNT-COOH immobilized on a carbon paste electrode were performed with wave square voltammetry (SWV). The analytical parameters pH, buffer composition, and amounts of MWCNT-COOH and MIP were investigated and optimized. Excellent results were obtained with a linear range of between 5.2 × 10 −8 and 1.25 × 10 −6 mol L −1, detection limit of 9.0 × 10 −9 mol L −1, and sensitivity of 5.1 × 10 5 μA L mol −1 . The MWCNT-COOH-MIP/CPE showed an enhanced electrochemical response, with sensitivity 7.9-fold greater than for a plain carbon paste electrode (CPE). Application of the sensor using river water samples resulted in recoveries between 96.1 and 99.5% and RSD <5% (n=3), demonstrating the reliability of this device.