Chemically modified halloysite nanotubes as a solid-phase microextraction coating

Area of Science:

• Analytical Chemistry
• Materials Science
• Environmental Science

Background:

• Organophosphate pesticides pose risks to environmental and human health.
• Developing sensitive and efficient analytical methods for pesticide detection is crucial.
• Halloysite nanotubes (HNTs) offer potential as novel adsorbent materials due to their unique structure.

Purpose of the Study:

• To develop and optimize a novel Solid-Phase Microextraction (SPME) coating using modified halloysite nanotubes (MHNTs).
• To evaluate the extraction efficiency of the MHNTs-based SPME coating for organophosphate pesticides.
• To apply the developed method for the analysis of pesticides in real environmental and food samples.

Main Methods:

• Halloysite nanotubes were modified via etching, hydroxylation, and amino grafting.
• Modified halloysite nanotubes (MHNTs) were chemically bonded to fused-silica support using the sol-gel technique.
• Gas chromatography-corona discharge ion mobility spectrometry (GC-CDMS) was used for the analysis of extracted pesticides (diazinon, parathion, fenthion).

Main Results:

• The MHNTs SPME coating demonstrated superior extraction efficiency compared to commercial SPME fibers and other bare/modified silica fibers.
• The method achieved low limits of detection (0.01-0.03 μg L⁻¹) and quantification (0.03-0.07 μg L⁻¹).
• Good linearity, high precision (RSD < 8.7%), and excellent recovery rates (84-97%) were obtained for pesticide analysis in real samples.

Conclusions:

• The developed MHNTs-based SPME method is highly efficient and sensitive for the determination of organophosphate pesticides.
• The method is suitable for the analysis of pesticides in complex matrices like agricultural wastewater and food samples.
• Modified halloysite nanotubes represent a promising material for advanced SPME applications in environmental monitoring.