Electrochemical and Quantum Chemical Investigations of the Insecticide Fipronil

Okumura, Fabiano; Amaral, Raquel Bonatto do; Orestes, Ednilsom; Silva, Albérico B.F.; Mazo, Luiz Henrique

doi:10.5935/0103-5053.20150347

Cited by 5 publications

(6 citation statements)

References 27 publications

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“…The atomic charges of these nitrogen atoms, such as N 19 , N 20 , and N 24 (atomic numbering depicted in Figure 1a), were previously estimated at −0.58, −0.77, and −0.56 (a.u. ), respectively, after fully unconstrained geometry optimization in aqueous phases [32]. Our DFT calculations of the atomic charges of these nitrogen atoms were also consistent with those data.…”

Section: Resultssupporting

confidence: 79%

Surface-Enhanced Raman Scattering Detection of Fipronil Pesticide Adsorbed on Silver Nanoparticles

Nguyen

Nghi

et al. 2019

Sensors

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This work presents a surface-enhanced Raman scattering (SERS) and density functional theory (DFT) study of a fipronil adsorbed on colloidal silver nanoparticles (AgNPs). A standard curve was established to quantify fipronil within a range of 0.0001–0.1 ppm (r2 ≥ 0.985), relying on the unique fipronil Raman shift at ~2236 cm−1 adsorbed on AgNPs. DFT calculations suggest that the nitrile moiety (C≡N) binding should be slightly more favorable, by 1.92 kcal/mol, than those of the nitrogen atom of the pyrazole in fipronil and Ag6 atom clusters. The characteristic peaks of the SERS spectrum were identified, and both the calculated vibrational wavenumbers and the Raman intensity pattern were considered. The vibrational spectra of fipronil were obtained from the potential energy distribution (PED) analysis and selective Raman band enhancement.

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Section: Resultssupporting

confidence: 79%

Surface-Enhanced Raman Scattering Detection of Fipronil Pesticide Adsorbed on Silver Nanoparticles

Nguyen

Nghi

et al. 2019

Sensors

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“…The wide use of fipronil has raised concerns because of the residual fipronil present in soil or aquatic ecosystems [20,23] given its threat to human health [24] . The methods reported for the analysis of fipronil are mostly chromatographic, [25] while recently some cheap and rapid techniques have emerged [26] including a few electrochemical methods [26c–h] . The method we evaluate in the present paper employing AdsSV on the aforementioned carbon electrodes, particularly on a CNT modified surface can be seen in principle as an electroanalytical method alternative to the existing analytical methods for fipronil determination.…”

Section: Introductionmentioning

confidence: 99%

Optimising Adsorptive Stripping Voltammetry: Strategies and Limitations

2021

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The widely employed electroanalytical technique of adsorptive stripping voltammetry (AdsSV) is critically assessed and evaluated at a wide and diverse range of unmodified and nanoparticle modified carbon electrodes using the analyte fipronil as a paradigmatic case. The generic electroanalytical performances of the nano-particle modified electrodes are investigated and compared with the unmodified electrodes revealing similar LOD values and pointing to intrinsic limitations of AdsSV arising from the non-independence of the Faradaic and capacitive signals during the stripping step. Methods for facilitating the adsorption or using different waveforms that may offer a more favourable limit of detection (LOD) at the nano-particle modified electrodes are suggested and assessed, specifically the use of adsorption onto particles prior to their use for modifying electrodes and also the recently introduced method of semicircular voltammetry.

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“…One analytical method for the determination of FPN was developed for natural water samples by square-wave voltammetry, employing a graphite–polyurethane (GPU) composite electrode. 19…”

Section: Introductionmentioning

confidence: 99%

“…32 One analytical method for the determination of FPN was developed for natural water samples by square-wave voltammetry, employing a graphite-polyurethane (GPU) composite electrode. 19 In this work, a novel, rapid, and simple method has been proposed and validated, based on voltammetric assays, with satisfactory recovery percentages and limits of detection. It has been applied as a screening method for the determination of FPN in lactose-free skim milk samples.…”

Section: Introductionmentioning

confidence: 99%