Rapid direct cathodic voltammetric determination of insecticide flonicamid by renewable silver-amalgam film electrode

ABSTRACT

The voltammetric characterisation and determination of insecticide flonicamid (N-cyanomethyl-4-(trifluoromethyl)nicotinamide) were performed for the first time using a simple electrochemical sensor, renewable silver-amalgam film electrode (Hg(Ag)FE). During the development of the direct cathodic square wave voltammetric method (SWV) for the determination of flonicamid, a voltammetric behaviour of a target analyte in aqueous Britton-Robinson buffer solution from pH 2.0 to pH 11.98 was examined. In the investigated pH range, the peak which appeared in the potential span between −0.86 V and −1.56 V vs. saturated calomel electrode depending on the applied pH value was chosen for analytical purposes. As optimal pH for the determination of flonicamid, pH 2.5 was selected. Cyclic voltammetric measurements at pH 2.5 confirmed that the electrode reaction mechanism is an irreversible reduction controlled by the diffusion of flonicamid at Hg(Ag)FE. The optimised Hg(Ag)FE-SWV method resulted in good linearity in the concentration range of 1.96–41.2 µg mL⁻¹ while the relative standard deviation of the method was 0.30%. Flonicamid was successfully determined in commercial formulation Teppeki 500 WG® and spiked river water sample by the developed method using the standard addition procedure. The average value of flonicamid amount found in a commercial formulation based on three repetitions was 497.8 ± 0.9 g kg⁻¹, which is in good agreement with the manufacturer’s declaration (500 ± 25 g kg⁻¹) and with comparative high-performance liquid chromatographic measurements with diode array detection where a found average value of flonicamid content was 497.5 ± 11.5 g kg⁻¹. The obtained results also indicate that the developed SWV procedure using Hg(Ag)FE was appropriate for the determination of flonicamid in a spiked river water sample with the recovery of 92.86% and RSD of 6.19%.

KEYWORDS:

• Flonicamid
• square wave voltammetry
• amalgam based electrode
• high-performance liquid chromatography
• commercial formulation
• river water sample

Acknowledgments

This paper is dedicated to the memory of our wonderful colleague and professor, Dr Valéria Guzsvány in remembrance of her great effort and conceptualization of this work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia [451-03-68/2022-14/200125]; CEEPUSIII network [CZ-0212-15-2122].