TITLE:
Validation of a Quantitative Electrochemical Method Using a Carbon Fiber Microelectrode for the Determination of Fenitrothion Residues in Soil
AUTHORS:
Boukaré Kaboré, Amidou Tall, Bibata Ouedraogo, Yibor Fabrice Roland Bako, Issa Tapsoba
KEYWORDS:
Fenitrothion, Carbon Fiber Microelectrode, Method Validation, Soil, ANOVA
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.17 No.8,
August
28,
2026
ABSTRACT: 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.