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
Received 17 A
Received in re
Accepted 8 No
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 . Many of these methods are accurate and ding author. ress: firstname.lastname@example.org (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 .
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 .
Hexazinone is a soft base and is a pervasive ground water contaminant due to its water solubility . 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 .
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
N). (For interp referred to the of the temp template is be degraded instability o ilar chemic in the synth
Molecul have been u acting with
The proces models of f and residue static, hydr .
Recent r carbon pas such as para , 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