Determination of azinphos-methyl in environmental samples using alkaline hydrolysis combined with spectroflourimetry and response surface modelling

ABSTRACT

The wide application of organophosphorus pesticides to control pests of agricultural products and the dangers of the residual of these toxins in the environment and food products on the health of humans and other living organisms have led to develop new methods for measuring these pesticides. The determination of azinphos-methyl AZM using alkaline hydrolysis combined with spectrofluorometry was done, and the experimental parameters were optimised by experimental design and response surface methodology (RSM). The effect of different factors, such as solvent, pH, time, and temperature on alkaline hydrolysis of azinphos-methyl, was screened using fractional factorial design and optimised by central composite design (CCD). The analysis of obtained response surface models showed a good fit of the experimental results to the second-order polynomial model with a coefficient of determination (R²) value of 0.9968. pH was set at 12 and water was selected as the solvent from desirability function. A linear calibration curve for fluorimetric determination of azinphos-methyl was obtained in the 5–1000 ngmL-1 range under ideal conditions with a detection limit of 1.013 ngmL⁻¹ and a correlation coefficient of 0.998. A relative standard deviation (RSD) of 1.36% was obtained for five consecutive replicates. Finally, the determination was carried out on spiked samples of the river water, as well.

KEYWORDS:

• Organophosphorus pesticides
• alkaline hydrolysis
• fluorimetry determination
• central composite design

Disclosure statement

No potential conflict of interest was reported by the authors.