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Indirect analysis of urea herbicides from environmental water using solid-phase microextraction
1Laboratori de Bromatologia i Toxicologia, Facultat de Farmàcia, Universitat de València, Burjassot, Spain.
Journal of Chromatography. A
|September 29, 2000
Summary
A new solid-phase microextraction method efficiently extracts urea pesticides from environmental samples. The polyacrylate fiber method offers sensitive detection and is validated for natural waters.
Area of Science:
- Environmental Chemistry
- Analytical Chemistry
Background:
- Urea pesticides pose environmental risks.
- Sensitive and efficient extraction methods are needed for their detection.
Purpose of the Study:
- To develop a sensitive solid-phase microextraction (SPME) method for six urea pesticides.
- To optimize extraction conditions and validate the method for environmental samples.
Main Methods:
- Comparison of polydimethylsiloxane and polyacrylate (PA) fibers for SPME.
- Optimization of extraction time, pH, NaCl concentration, and humic acid influence.
- Determination by gas chromatography with nitrogen-phosphorus detection (GC-NPD).
Main Results:
- The PA fiber demonstrated superior extraction efficiency.
- Optimized conditions: 2 ml sample, pH 4, 14.3% NaCl, 60 min extraction.
- Detection limits ranged from 0.04 to 0.1 µg/l with good precision (RSD 9-15%).
Conclusions:
- The developed SPME-GC-NPD method is sensitive and suitable for analyzing urea pesticides in natural waters.
- Humic acid can interfere, but NaCl addition mitigates this effect.
- LC-MS is recommended for unequivocal identification in complex environmental samples.