Introduction:
Acetochlor is a commonly employed herbicide that can accumulate in agricultural products, including corn (Zea mays), as well as in medicinal plant materials such as corn silk, posing a potential health risk. The objective of the research was to develop a method for the quantitative determination of acetochlor in medicinal plant raw materials (corn silk) using the fluorescence polarization immunoassay (FPIA) method.

Methods:
Polyclonal rabbit antibodies to acetochlor and a tracer labeled with fluorescein acetochlor AMPA-EDF were used to develop the method. The analysis was performed using the fluorescence polarization method on a Sentry-200 portable fluorimeter (Ellie LLC), the data were processed using the Sigma Plot 11 software package (Systat Software Inc., USA). The analysis was conducted using medicinal raw materials of corn silk, purchased at a local pharmacy. Method validation was performed for the following parameters: analytical range, specificity, accuracy, and precision.

Results:
A method for quantitative determination of the pesticide acetochlor in corn silk (Zea mays) raw materials using FPIA was developed, optimized, and validated. Acetochlor extraction from plant material was performed using water followed by liquid-liquid extraction into hexane. The method demonstrated a detection range of 2.4×10⁻³ to 0.072 mg/kg, corresponding to 8-240% of the maximum permissible level (0.03 mg/kg) established by regulatory standards. No cross-reactivity with butachlor or metolachlor was observed at concentrations corresponding to IC₂₀ (0.04 μg/mL). The method was proven to be specific, precise, and accurate. Analysis of corn silk samples revealed acetochlor concentrations ranging from 0.3 to 1.3 μg/kg.

Conclusion:
A method for rapid quantification of the pesticide acetochlor in corn silk (Zea mays) medicinal raw materials was developed using fluorescence polarization immunoassay (FPIA).