A molecularly imprinted polymer for the selective solid-phase extraction of dimethomorph from ginseng samples

Area of Science:

• Analytical Chemistry
• Polymer Science
• Food Safety

Background:

• Dimethomorph is a widely used fungicide, and its presence in food products like ginseng needs accurate monitoring.
• Selective extraction methods are crucial for detecting low concentrations of pesticides in complex matrices.
• Existing methods may suffer from interference or low efficiency.

Purpose of the Study:

• To develop and evaluate a molecularly imprinted polymer (MIP) for the selective extraction of dimethomorph from ginseng samples.
• To establish a sensitive and reliable analytical method for dimethomorph determination.
• To validate the performance of the proposed method in terms of sensitivity, accuracy, and precision.

Main Methods:

• Synthesis of dimethomorph-specific MIPs using precipitation polymerization with methacrylic acid and ethylene dimethacrylate.
• Molecularly imprinted solid-phase extraction (MISPE) for sample preparation.
• Gas chromatography (GC) for quantitative analysis of dimethomorph.
• Optimization of template-to-monomer molar ratios and porogen composition (butanone:N-heptane).

Main Results:

• The developed MIP exhibited high selectivity for dimethomorph extraction.
• The method achieved a low limit of detection (LOD) of 0.002 mg kg(-1) and limit of quantification (LOQ) of 0.005 mg kg(-1).
• Average recoveries ranged from 89.2% to 91.6% across different spiked levels (0.1-5.0 mg kg(-1)).
• Excellent linearity (r(2) ≥ 0.9997) was observed in the range of 0.01-5 mg kg(-1) with relative standard deviations below 3.20%.

Conclusions:

• The proposed MISPE-GC procedure effectively eliminates template leakage, ensuring accurate quantitative analysis.
• The developed MIP-based method is suitable for the direct and reliable determination of dimethomorph in ginseng samples.
• This approach offers a promising tool for pesticide residue monitoring in agricultural products.