Factors affecting multiresidue determination of priority herbicides when using solid-phase microextraction

Area of Science:

• Environmental Chemistry
• Analytical Chemistry

Background:

• Organonitrogen herbicides are widely used in agriculture.
• Monitoring these herbicides in natural waters is crucial for environmental protection.
• Existing analytical methods can be complex and time-consuming.

Purpose of the Study:

• To develop and optimize a solid-phase microextraction (SPME) method for determining 10 organonitrogen herbicides.
• To evaluate the method's performance in various natural water matrices.
• To compare SPME with conventional solid-phase extraction for herbicide analysis.

Main Methods:

• Solid-phase microextraction (SPME) using polydimethylsiloxane and polyacrylate fibers.
• Gas chromatography coupled with flame thermionic and mass spectrometric detection.
• Optimization of SPME parameters including pH, ionic strength, methanol content, stirring rate, and adsorption time.

Main Results:

• Optimal SPME conditions determined: 25% salt, <0.5% methanol, 960 rpm stirring, pH 4, 30 min adsorption.
• Method successfully applied to spiked ground water, sea water, lake water, and river water (0.5-10 µg/L).
• Limits of detection: 5-90 ng/L; precision: 5-15%; recoveries: 70.2-118.4%.

Conclusions:

• The developed SPME method is suitable for the reliable determination of 10 organonitrogen herbicides in diverse natural water samples.
• SPME offers a sensitive and efficient alternative to conventional extraction techniques for herbicide monitoring.
• The method was validated using real river water samples from Northwestern Greece.