Optimization of fiber coating structure enables direct immersion solid phase microextraction and high-throughput...

Area of Science:

• Analytical Chemistry
• Materials Science

Background:

• Solid-phase microextraction (SPME) is a widely used technique for sample preparation.
• Current SPME fiber coatings, such as poly(dimethyl siloxane)/divinyl benzene (PDMS/DVB), can suffer from limited robustness, especially in complex matrices.
• Improving fiber durability is crucial for high-throughput analysis and automation.

Purpose of the Study:

• To develop a more robust SPME fiber coating for gas chromatography (GC) analysis.
• To enhance the structural integrity of commercial PDMS/DVB SPME fibers.
• To evaluate the performance of the modified fiber in complex sample matrices.

Main Methods:

• A novel approach involving the application of an external poly(dimethyl siloxane) (PDMS) layer over a commercial PDMS/divinyl benzene (DVB) extraction phase was employed.
• The modified SPME fiber was tested for the extraction of triazole pesticides from water samples.
• The fiber's performance was evaluated in direct contact with a complex food matrix (whole grape pulp) over multiple extraction cycles.

Main Results:

• The modified SPME fiber exhibited extraction capabilities comparable to the original PDMS/DVB fiber for triazole pesticides in water.
• The enhanced fiber demonstrated exceptional robustness, withstanding over 100 extractions directly from whole grape pulp without sample pretreatment.
• Relative standard deviations (RSD) for extracted pesticides from grape pulp remained below 20% throughout 130 extraction/desorption/conditioning cycles.

Conclusions:

• The external PDMS coating significantly improves the structural robustness and durability of SPME fibers.
• The enhanced SPME fiber is suitable for high-throughput automated analysis of pesticides in complex food matrices.
• This advancement facilitates simplified sample preparation and increased analytical efficiency.