Multi-response optimization and validation analysis in the detection of acetochlor and butachlor by HPLC based on...

Acetochlor and butachlor, widely used herbicides, pose environmental and health risks through water contamination. This study developed a high-performance liquid chromatography (HPLC) method for analyzing these compounds, employing a multi-response approach and D-optimal design. The D-optimal design reduced the number of required experiments from 36 to 14. The response model was analyzed by variance and residual diagnosis, and a multi-response optimization process was implemented to minimize the retention time and maximize the peak area of the two analytes. The optimal conditions were determined: a column temperature of 30 °C, a mobile phase composition of 80:0:20 (CH₃OH:CH₃CN:H₂O) by volume, a flow rate of 0.9 mL min^-1, an injection volume of 25 μL, and a detection wavelength of 215 nm. The method achieved complete separation of acetochlor and butachlor within 10 min. The detection limits were 0.0018 mg L^-1 for acetochlor and 0.01 mg L^-1 for butachlor, with quantitation limits of 0.009 mg L^-1 and 0.06 mg L^-1, respectively. The linear ranges extended from 0.009 to 9 mg L^-1 for acetochlor and 0.06 to 15 mg L^-1 for butachlor, with a correlation coefficient (R²) of 0.9998, indicating excellent linearity. The recoveries ranged from 98.36 % to 103.13 % for acetochlor and 80.30 % to 107.74 % for butachlor, with the relative standard deviations both below 2 % (n = 6). This accurate, rapid, and sensitive method is well-suited for quantitative detection of these herbicides in water. It also serves as an invaluable reference for analyzing structurally similar chloroacetamide herbicides using HPLC.