• Nada, S. Abdelwahab
• Eglal, A. Abdelaleem
• Moustafa, M. Elmasri
• Mona, A. Mohamed
• Beloglazova, Natalia
• De Saeger, Sarah
• Elakaad, Suzan

Abstract

Food and environmental safety are a worldwide challenge tohuman health. Continuous monitoring of food and environmental contaminants through the development of novel and sensitive analytical techniques is a must. Among these contaminants are pesticides which are broadly used by farmers to control crop diseases. These chemicals and their metabolites are usually accumulating in plant tissues and in water which eventually will have negative public health effects on consumers. The detection of these contaminants mainly depends on separation technologies such asliquid or gas chromatography coupled with a mass spectrometer or an immunological interaction such as in enzyme-linked immunosorbent assays. Despite being sensitive and specific, all these techniques require the use of expensive equipment and highly trained personnel which limit their applications in many countries with poor equipped facilities and specialists. To cope with this obstacle, nanomaterials-based biosensors have been proposed as rapid, sensitive, efficient and portable alternatives to the traditional detection techniques. Therefore, in this work we present for the first time a novel electrochemical sensor based on a carbon paste electrode (CPE) modified with bismuth ferrite nanoparticles (BiFeO3/CPE) to detect two of the most commonly used pesticides in agriculture worldwide (imidacloprid “IMD” and fipronil “FIP”). IMD was introduced to the market in 1992 as a first member of the neonicotinoids class (neonics). Neonics and FIP applications in seed and soil represent around 60% of pesticides worldwide. Moreover, IMD usage accounts for 41.5% of the whole neonics market. IMD and FIP were found to be toxic to sensitive aquatic invertebrates at very low concentrations (<100 ng/L). Their chemical properties in addition to their impact on pollinators (honeybees and bumble bees) have raised an EU concern. Therefore, monitoring of both analytes in water is essential to reduce their negative impacts on health and environment. The modified- CPE showed a synergetic effect towards the oxidationof IMD and FIP. The prepared nanoparticles were investigated and characterized using SEM, TEM, XRD and FT-IR. The described voltammetric technique was optimized and validated. Under the optimal conditions, the sensor showed a sensitive response to their determination over a linear range (1 μM – 100 μM) in water. The detection limits (LODs) for IMD and FIP were determined as 0.97 μM and 1.27 μM, respectively. The recovery percentagesfor IMD and FIP in environmental water samples varied from 90 %-105 %. In conclusion, the developed sensor was successfully optimized and can be used for the simultaneous detection of both IMD and FIP in environmental water samples.

Topics

• nanoparticle
• impedance spectroscopy
• Carbon
• scanning electron microscopy
• x-ray diffraction
• transmission electron microscopy
• gas chromatography
• Bismuth
• cloud-point extraction