A New Spectrophotometric Determination of a Pyrethroid Insecticide by Diazotization-Coupling Reaction

A novel and sensitive spectrophotometric technique for identifying alpha-cypermethrin insecticide when coupled with 5-amino-2-hydroxybenzoic acid in an alkaline medium with a pH of about 9–10 was investigated to enhance its analytical detectability to produce yellow-red azo dye. The reaction product was characterized using UV-Vis spectrophotometry (FTIR), ¹H-NMR, and ¹³C-NMR. Acetone and Triton X-100 are used as solvents to increase the solubility and the sensitivity of the procedure. At 25°C, the colored product remained stable for nearly two days. The maximum absorbance was observed at λmax 408 nm. The range of (1-100) µg.mL⁻¹ is where the Beer-Lambert law is followed. The developed method was analytically validated. The limit of detection was found to be (0.130) µg.mL⁻¹, and the limit of quantification was (0.433) µg.mL⁻¹, indicating high sensitivity. The process is efficient for large-scale synthesis, has strong functional-group tolerance, and has gentle reaction conditions, suggesting a promising approach for selective and sensitive analytical monitoring in environmental and agricultural samples.