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Method validation for strobilurin fungicides in cereals and fruit
1Danish Veterinary and Food Administration, Søborg. hbc@fdir.dk
Food Additives and Contaminants
|September 25, 2001
Summary
A validated gas chromatography (GC) method accurately analyzes strobilurin fungicides in crops. This method, using electron capture, nitrogen/phosphorous, and mass spectrometric detection, shows good recovery and low detection limits for azoxystrobin, kresoxim-methyl, and trifloxystrobin.
Area of Science:
- Agricultural Chemistry
- Analytical Chemistry
- Environmental Science
Background:
- Strobilurins represent a significant class of broad-spectrum fungicides.
- Accurate analytical methods are crucial for monitoring fungicide residues in food products.
Purpose of the Study:
- To validate a gas chromatography (GC) method for the analysis of three strobilurin fungicides: azoxystrobin, kresoxim-methyl, and trifloxystrobin.
- To assess the method's performance across different matrices (wheat, apple, grapes) and detection techniques.
Main Methods:
- Extraction using ethyl acetate/cyclohexane.
- Clean-up via gel permeation chromatography (GPC).
- Determination by GC with electron capture (EC), nitrogen/phosphorous (NP), and mass spectrometric (MS) detection.
Main Results:
- Mean recoveries ranged from 70-114% across detectors and matrices.
- Limits of detection (LODs) were between 0.004-0.014 mg/kg for all strobilurins.
- Repeatability and reproducibility values aligned with the Horwitz equation, with exceptions for azoxystrobin in grapes and apple (MS).
Conclusions:
- The validated GC method is suitable for quantifying strobilurin fungicides in wheat, apple, and grape matrices.
- Matrix-matched standards may be necessary due to observed differences in calibration curves.
- Further validation is needed for specific analyte-matrix-detector combinations, particularly azoxystrobin.