title: Glyphosate detection by means of a voltammetric electronic tongue and discrimination of potential interferents.
abstract: A new electronic tongue to monitor the presence of glyphosate (a non-selective systemic herbicide) has been developed. It is based on pulse voltammetry and consists in an array of three working electrodes (Pt, Co and Cu) encapsulated on a methacrylate cylinder. The electrochemical response of the sensing array was characteristic of the presence of glyphosate in buffered water (phosphate buffer 0.1 mol · dm-3, pH 6.7). Rotating disc electrode (RDE) studies were carried out with Pt, Co and Cu electrodes in water at room temperature and at pH 6.7 using 0.1 mol · dm-3 of phosphate as a buffer. In the presence of glyphosate, the corrosion current of the Cu and Co electrodes increased significantly, probably due to the formation of Cu2+ or Co2+ complexes. The pulse array waveform for the voltammetric tongue was designed by taking into account some of the redox processes observed in the electrochemical studies. The PCA statistical analysis required four dimensions to explain 95% of variance. Moreover, a two-dimensional representation of the two principal components differentiated the water mixtures containing glyphosate. Furthermore, the PLS statistical analyses allowed the creation of a model to correlate the electrochemical response of the electrodes with glyphosate concentrations, even in the presence of potential interferents such as humic acids and Ca2+. The system offers a PLS prediction model for glyphosate detection with values of 098, -2.3 × 10-5 and 0.94 for the slope, the intercept and the regression coefficient, respectively, which is in agreement with the good fit between the predicted and measured concentrations. The results suggest the feasibility of this system to help develop electronic tongues for glyphosate detection.
authors.affiliation: Centro de Reconocimiento Molecular y Desarrollo Tecnológico (IDM), Unidad Mixta Universidad Politécnica de Valencia-Universidad de Valencia de Valéncia, Camino de Vera s/n, E-46022 Valencia, Spain. robapra@upvnet.upv.es
authors.forename: Román
authors.initials: R
authors.lastname: Bataller
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Campos
authors.forename: Nicolas
authors.initials: N
authors.lastname: Laguarda-Miro
authors.forename: Miguel
authors.initials: M
authors.lastname: Alcañiz
authors.forename: Juan
authors.initials: J
authors.lastname: Soto
authors.forename: Ramón
authors.initials: R
authors.lastname: Martínez-Máñez
authors.forename: Luís
authors.initials: L
authors.lastname: Gil
authors.forename: Eduardo
authors.initials: E
authors.lastname: García-Breijo
authors.forename: Javier
authors.initials: J
authors.lastname: Ibáñez-Civera
mesh_terms: D055664:Electrochemical Techniques; D004581:Electronics; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification; D006540:Herbicides / Q000737:chemistry / Q000302:isolation & purification*; D006801:Humans; D007202:Indicators and Reagents; D025341:Principal Component Analysis; D000097797:Glyphosate
chemical_list: D005998:Glycine; D006540:Herbicides; D007202:Indicators and Reagents; D000097797:Glyphosate