Determining Pesticides Using a Nanofibrous Double-Layered Biosorbent

Scientists from the University of Tehran in Iran determined multiclass pesticides in water samples using a new type of novel nanofibrous double-layered biosorbent. Their findings were published in the Journal of Chromatography A (1).

Tractor spraying pesticides at corn fields | Image Credit: © Vesna - stock.adobe.com

Pesticides can be essential for crop protection but are also harmful to humans and persist in the environment. Monitoring pesticide residues is vital for food safety, environmental protection, regulatory enforcement, and consumer exposure assessment. These substances are intrinsically toxic and deliberately spread in the environment, with strict regulation and control being called for their production, distribution, and use.

Read More: Using UHPLC-MS/MS to Test for Pesticides

Biosorption is a physico-chemical and metabolically independent process based on various mechanisms, including absorption, adsorption, ion exchange, and other processes. A branch of biotechnology, this process has been aimed at removing or recovering organic and inorganic substances from a solution by biological material; this can include living or dead microorganisms and their components, seaweeds, plant materials, industrial and agricultural wastes, and natural residues (2).

In this study, a novel nanofibrous double-layered biosorbent was fabricated (1). This system was developed through electrospinning polyethersulfone (PES) doped with a natural deep eutectic solvent (DES), composed of choline chloride (ChCl) and caffeic acid (CFA) in a 3:1 molar ratio, onto a bacterial cellulose (BC) substrate (1). The biosorbent was then employed in a thin film-solid phase microextraction (TF-SPME) to extract 12 multiclass pesticides from water. Characterization techniques, such as attenuated total reflectance-Fourier transform infrared (ATR-FTIR), FT-nuclear magnetic resonance (NMR), scanning electron microscope (SEM), and nitrogen adsorption/desorption isotherms, were used to confirm the nanofibrous structure of the electrospun PES-DES and BC substrate.

The method was then validated for matrix effect, specificity, reproducibility, limits of quantification (0.03–0.10 µg/L), and enrichment factor. Matrix-match calibration linearity ranged from 0.03–500 µg/L, with determination coefficients (r²) between 0.9884 and 0.9994. Intra-day and inter-day relative standard deviations (RSDs) were 1.2–3.6% and 7.0–9.3%, respectively.

The composition of the biosorbent and fabrication reproducibility across different batches were also thoroughly examined. As for the accuracy, it was evaluated through measuring extraction recoveries in six environmental water samples, which ranged from 75–105%. The method’s sustainability was evaluated using Analytical Eco-Scale and Analytical Greenness metrics. The former system is based around assigning penalty points to parameters of an analytical process that clash with ideal green analysis. Further, it compares different parameters and different steps of the analytical process (3). As for the Analytical GREEnness Calculator, it is thought of as “a comprehensive, flexible, and straightforward assessment approach that provides an easily interpretable and informative result,” according to scientists from the Gdańsk University of Technology in Poland and the University of Vigo in Spain (4). According to the scientists, “this study represents the first synthesis and combination of [ChCl:[CFA] DES with PES to create a double-layered nanofiber biosorbent, as well as its application for extracting various pesticide groups from water samples.”

Overall, the novel double-layered nanofibrous biosorbent in the study shows promise as an adsorbent and membrane for extracting pesticides and other organic pollutants from diverse water samples. Its properties can be contributed to its eco-friendliness, porous structure, and low density.

References

(1) Mokarami, M. S. A.; Sereshti, H. Fabrication of a Green Double-Layered Hybrid Nanocomposite via Electrospinning of Polyethersulphone/Natural Deep Eutectic Solvent on Bacterial Cellulose for Determination of Multiclass Pesticides in Water Samples. J. Chromatogr. A 2024, 1735, 465267. DOI: 10.1016/j.chroma.2024.465267

(2) Fomina, M.; Gadd, G. M. Biosorption: Current Perspectives on Concept, Definition and Application.Bioresour. Technol. 2014, 106, 3–14. DOI: 10.1016/j.biortech.2013.12.102

(3) Gałuszka, A.; Migaszewski, Z. M.; Konieczka, P.; et al. Analytical Eco-Scale for Assessing the Greenness of Analytical Procedures. TrAC Trends Analyt. Chem. 2012, 37, 61–72. DOI: 10.1016/j.trac.2012.03.013

(4) Pena-Pereira, F.; Wojnowski, W.; Tobiszewski, M. AGREE—Analytical GREEnness Metric Approach and Software. Anal. Chem. 2020, 92 (14), 10076–10082. DOI: 10.1021/acs.analchem.0c01887