A square wave voltammetric method using a carbon fiber microelectrode (CFME) in 0.1 M phosphate-buffered saline (PBS) was developed and fully validated for the quantitative determination of fenitrothion (FNT) residues in soil, according to EURACHEM/CITAC guidelines and ISO/IEC 17025 requirements. FNT exhibited an irreversible diffusion-controlled cathodic peak at ？1.02 V vs. saturated calomel electrode (SCE). Method validation supported by statistical analyses, including ANOVA, was employed. Key parameters such as pH, pulse amplitude, frequency, and step increments influencing the cathodic peak were optimized. Among the tested interferents, only 3-methyl-4-nitrophenol (MNP) significantly affected FNT detection, while no matrix effects were observed. The calibration curve was assessed using linear regression, which showed that the optimal line of best fit minimizes the sum of squared residuals. The calibration curve was linear in the range of 10 - 200 μg·L？1 with R2 = 0.9997. Recovery rates varied from 89.12% to 94.76%, with relative standard deviations (RSDs) between 1.19% and 1.47%. The method precision was confirmed with within-day and between-day RSDs of 1.404% and 1.579%, respectively. Good reproducibility was observed through comparative analysis by gas chromatography with a Nitrogen Phosphorus Detector (GC-NPD). LOD and LOQ were estimated and were close to 6.56 μg·kg？1 and 19.87 μg·kg？1, respectively. The FNT stock solution remained stable for at least three months at 7？C. Measurement uncertainty was estimated as U = 0.04399 × C using the GUM approach. This validated electrochemical method offers a simple, accurate, and reliable approach suitable for environmental monitoring of FNT residues in soil.
References
[1]
Geremedhin, W., Amare, M. and Admassie, S. (2013) Electrochemically Pretreated Glassy Carbon Electrode for Electrochemical Detection of Fenitrothion in Tap Water and Human Urine. Electrochimica Acta, 87, 749-755. https://doi.org/10.1016/j.electacta.2012.09.046
[2]
Richard, P.P. (2014) Sittig’s Handbook of Pesticides and Agricultural Chemicals. 2nd Edition, William Andrew.
[3]
International Programme on Chemical Safety (1992) Environmental Health Criteria 133—Fenitrothion. https://iris.who.int/bitstreams/e6f51b6f-8522-44f9-b03b-309a8ba0e1fc/download
[4]
Australian Pesticides and Veterinary Medicines Authority (2024) Fenitrothion Review Technical Report. https://www.apvma.gov.au/sites/default/files/2024-04/Fenitrothion%20-%20Review%20Technical%20Report.pdf
[5]
Wijeyesakere, S.J. and Richardson, R.J. (2010) Neuropathy Target Esterase. In: Krieger, R., Ed., Hayes’ Handbook of Pesticide Toxicology, 3rd Edition, Elsevier, 1435-1455. https://doi.org/10.1016/b978-0-12-374367-1.00067-7
[6]
Tefera, M., Tessemaa, M., Admassiea, S. and Mehretiea, S. (2015) Electrochemical Sensor for Determination of Fenitrothion at Multi-Wall Carbon Nanotubes Modified Glassy Carbon Electrode. Analytical and Bioanalytical Chemistry Research, 2, 139-150.
[7]
Zelayaran, L.M. and Machado, S.A.S. (2005) Determination of Fenitrothion in Commercial Formulations by Square Wave Voltammetry and UV-Vis Spectroscopy. Journal of the Brazilian Chemical Society, 16, 743-748. https://doi.org/10.1590/s0103-50532005000500011
[8]
Sánchez, M.E., Méndez, R., Gómez, X. and Martín-Villacorta, J. (2003) Determination of Diazinon and Fenitrothion in Environmental Water and Soil Samples by HPLC. Journal of Liquid Chromatography & Related Technologies, 26, 483-497. https://doi.org/10.1081/jlc-120017184
[9]
Malhat, F., Boulangé, J., Abdelraheem, E., Abd Allah, O., Abd El-Hamid, R. and Abd El-Salam, S. (2017) Validation of QuEChERS Based Method for Determination of Fenitrothion Residues in Tomatoes by Gas Chromatography-Flame Photometric Detector: Decline Pattern and Risk Assessment. Food Chemistry, 229, 814-819. https://doi.org/10.1016/j.foodchem.2017.03.017
[10]
Baroja, O., Unceta, N., Sampedro, M.C., Goicolea, M.A. and Barrio, R.J. (2004) Optimization and Validation of a Method of Analysis for Fenitrothion and Its Main Metabolites in Forestry Air Samples Using Sorbent Tubes with Thermal Desorption Cold Trap Injection and Gas Chromatography-Mass Spectrometry. Journal of Chromatography A, 1059, 165-170. https://doi.org/10.1016/j.chroma.2004.10.038
[11]
Aly, M.I., Fouad, R.M., Abou-Elnasr, S.H. and El-Aswad, F.A. (2021) Comparison of Dissipation Kinetics and Residual Behaviour for Fenitrothion Insecticide and Thiobencarb Herbicide in Clay Soil. Alexandria Journal of Agricultural Sciences, 66, 1-11.
[12]
Liu, X.S., Li, Y.T., Qiao, W.L., Chang, M.J. and Li, Y. (2023) A Non-Enzymatic Electrochemical Sensor Based on Nitrogen-Doped Mesoporous Carbon@hydroxyl-Functionalized Ionic Liquid Composites Modified Electrode for the Detection of Fenitrothion. RSC Advances, 13, 13030-13039.
[13]
Wang, R., Wang, S., Qin, C., Nie, Q., Luo, Y., Qin, Q., et al. (2022) An Electrochemical Sensor Based on Electropolymerization of β-Cyclodextrin on Glassy Carbon Electrode for the Determination of Fenitrothion. Sensors, 23, Article No. 435. https://doi.org/10.3390/s23010435
[14]
Majidi, M.R., Asadpour-Zeynali, K. and Nazarpur, M. (2009) Determination of Fenitrothion in River Water and Commercial Formulations by Adsorptive Stripping Voltammetry with a Carbon Ceramic Electrode. Journal of AOAC International, 92, 548-554. https://doi.org/10.1093/jaoac/92.2.548
[15]
Allen, J.B. and Larry, R.F. (2001) Electrochemical Methods: Fundamentals and Applications. 2nd Edition, John Wiley & Sons, Inc. https://electrochem.xmu.edu.cn/UserFiles/File/Electrochemical%20methods.%20Fundamentals%20and%20applications.pdf
[16]
Tapsoba, I., Bourhis, S., Feng, T. and Pontié, M. (2009) Sensitive and Selective Electrochemical Analysis of Methyl-Parathion (MPT) and 4-Nitrophenol (PNP) by a New Type p-NiTSPc/p-PPD Coated Carbon Fiber Microelectrode (CFME). Electroanalysis, 21, 1167-1176. https://doi.org/10.1002/elan.200804529
[17]
Tapsoba, I., Paré, S., Toé, A., Kaboré, B., Koulibaly, B. and Bonzi-Coulibaly, Y. (2013) SWV Determination of Glyphosate in Burkina Faso Soils Using Carbon Fiber Microelectrode. International Journal of Biological and Chemical Sciences, 6, 2211-2220. https://doi.org/10.4314/ijbcs.v6i5.27
[18]
Bako, Y.F.R., Mbokou, S.F., Kaboré, B., Tapsoba, I. and Pontié, M. (2024) Indirect Electroanalysis of 3-Methyl-4-Nitrophenol in Water Using Carbon Fiber Microelectrode Modified with Nickel Tetrasulfonated Phthalocyanine Complex. Materials Sciences and Applications, 15, 25-35. https://doi.org/10.4236/msa.2024.152003
[19]
International Standard ISO/IEC 17025 (2017) General Requirements for the Competence of Testing and Calibration Laboratories. 3rd Edition. https://www.iso.org/standard/66912.html
[20]
Cantwell, H. (2025) Eurachem Guide: The Fitness for Purpose of Analytical Methods—A Laboratory Guide to Method Validation and Related Topics. 3rd Edition. https://www.eurachem.org/index.php/3-publications/guides/144-gdmv2014
[21]
Thompson, M., Ellison, S.L.R. and Wood, R. (2002) Harmonized Guidelines for Single-Laboratory Validation of Methods of Analysis (IUPAC Technical Report). Pure and Applied Chemistry, 74, 835-855. https://doi.org/10.1351/pac200274050835
[22]
Bako, Y.F.R., Kaboré, B., Tall, A., Sawadogo, W.F. and Tapsoba, I. (2026) Direct Electrochemical Analysis of 3-Methyl-4-nitrophenol in Water Using Carbon Fiber Microelectrode Modified with Nickel Tetrasulfonated Phthalocyanine Complex. Materials Sciences and Applications, 17, 1-14. https://doi.org/10.4236/msa.2026.171001
[23]
Galeano-Díaz, T., Guiberteau-Cabanillas, A., Espinosa-Mansilla, A. and López-Soto, M.D. (2008) Adsorptive Stripping Square Wave Voltammetry (Ad-SSWV) Accomplished with Second-Order Multivariate Calibration: Determination of Fenitrothion and Its Metabolites in River Water Samples. Analytica Chimica Acta, 618, 131-139. https://doi.org/10.1016/j.aca.2008.04.058
[24]
Ellison, S.L.R. and Williams, A. (Eds.) (2012) Eurachem/CITAC Guide: Quantifying Uncertainty in Analytical Measurement. 3rd Edition. https://www.eurachem.org/index.php/publications/guides/quam
