A new biomimetic sensor based on molecularly imprinted polymers for highly sensitive and selective determination of hexazinone herbicideby Maricely Janette Uria Toro, Luiz Diego Marestoni, Maria Del Pilar Taboada Sotomayor

Sensors and Actuators B: Chemical

Text

Sensors and Actuators B 208 (2015) 299–306

Contents lists available at ScienceDirect

Sensors and Actuators B: Chemical jo ur nal home page: www.elsev ier .com/ locate /snb

A new y i for high n o herbici

Maricely l Pi

Department of 801-97 a r t i c l

Article history:

Received 17 A

Received in re

Accepted 8 No

Available onlin

Keywords: 1,3,5-Triazine

Hexazinone

Molecularly imprinted polymer

Carbon paste sensor

Molecular modeling ecula ironm ers l mon ide (M cond ere m

HXZ determination was performed using differential pulse adsorptive cathodic stripping voltammetry (DPAdCSV). All parameters affecting the sensor response were optimized. In HCl at pH 2.5, the sensor prepared with MP17 (5% w/w in the paste) showed a dynamic linear range between 1.9 × 10−11 and 1.1 × 10−10 mol L−1, and a detection limit of 2.6 × 10−12 mol L−1, under the following conditions: accumulation time of 200 s at a potential of −0.5 V, scan rate of 50 mV s−1, pulse amplitude of 60 mV, and 1. Introdu

Herbicid used in agr low cost. Th of herbicide eral classes and cyanaz and metrib (bromoxyn commonly in agricultu of health ca

Identific ried out by mass spect by gas chro metric dete ∗ Correspon

E-mail add http://dx.doi.o 0925-4005/© pulse width of 50 ms. The sensor was selective in the presence of other similar compounds, and was successfully applied to the analysis of HXZ in river water samples. © 2014 Elsevier B.V. All rights reserved. ction es that act as inhibitors of photosystem II are widely iculture, since they provide effective weed control at is group accounts for about 30% of the total quantity s currently used in agriculture. They encompass sevof compounds, including triazines (atrazine, simazine, ine), diazines (bentazone), triazinones (hexazinone uzin), phenylureas (diuron and tebuthiuron), phenols il), and phenylamide. These harmful substances are found in surface and underground waters, as well as ral products, and their detection is important in terms re and on economic grounds [1,2]. ation and quantification of pesticides is routinely carhigh performance liquid chromatography, with either rometric or diode array detection [3–5], as well as matography with atomic emission or mass spectroction [6]. Many of these methods are accurate and ding author. ress: mpilar@iq.unesp.br (M.D.P.T. Sotomayor). selective, but require relatively expensive instrumentation and involve high consumption of reagents, which render them expensive or time consuming. Moreover, pesticides are usually found in trace amounts in water, so that extraction or pre-concentration steps must be performed prior to analysis [7].

Hexazinone (Chart 1) is the active compound of the herbicide

Velpar®, which is used to control a wide variety of broadleaf weeds, grasses, and woody plants in nurseries and forestry plantations. It is also used in sugar cane and pineapple plantations, pasture, and industrial sites [8].

Hexazinone is a soft base and is a pervasive ground water contaminant due to its water solubility [8]. In the literature, discussion of the chemistry of the reduction reaction of substituted 1,3,5triazines in aqueous media is restricted to observations of reduction waves and identification of the optimum conditions for their determination [9].

Molecularly imprinted polymers (MIPs) have been created to mimic (to a certain degree) biological receptors. They possess molecular recognition sites designed for a specific molecule. Polymer complexes are formed between the template and one or more functional monomers in an appropriate solvent. Polymerization then occurs in the presence of a cross-linker, and further removal rg/10.1016/j.snb.2014.11.036 2014 Elsevier B.V. All rights reserved.biomimetic sensor based on molecularl ly sensitive and selective determinatio de

Janette Uria Toro, Luiz Diego Marestoni, Maria De

Analytical Chemistry, Institute of Chemistry, State University of São Paulo (UNESP), 14 e i n f o pril 2014 vised form 18 October 2014 vember 2014 e 15 November 2014 a b s t r a c t

A new selective sensor based on mol mination of hexazinone (HXZ) in env approach, and selection of the monom molecular modeling. Three functiona (methacrylic acid (MP12) and acrylam for preparation of the MIPs, in order to sensor construction, carbon pastes wmprinted polymers f hexazinone lar Taboada Sotomayor ∗ 0 Araraquara, SP, Brazil rly imprinted polymers (MIPs) was developed for the deterental samples. MIPs were synthesized using a non-covalent employed in the polymerization reaction was carried out by omers with high (2-vinylpyridine (MP17)) and intermediate

P5)) energies of binding to the template (HXZ) were selected uct comparative studies and validate the theoretical data. For odified with each MIP or NIP (non-imprinted polymer), and 300 M.J.U. Toro et al. / Sensors and Actuators B 208 (2015) 299–306

Chart 1. Chem is as follows: w

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Recent r carbon pas such as para [13], and pr design MIPs tion proces using a carb

This wo ularly imp hexazinone was prepar molecular m 2. Materia 2.1. Reagen

The pes desethyl at (acrylamide and 2,2-azo powder (pa from Sigma obtained fro purchased and were p tion of hex and N,N-dim prepared w obtained fro 2.2. Compu

The com ware for m of MIPs. The OpenEye program VIDA v. 3.0.0 was used to visualize the modeled molecules and check for possible errors in the bonds between atoms. OpenEye Omega 2 was used to generate different conformers of molecules, in order to identify possible hindrances. By default, 10 conformers of each pesticide gene ulat e the stat omm the the

OPA app te (H . sim azino ogra to ob nform inter ions imat epar tem wit