Enhanced microfluidic open interface for the direct coupling of solid phase microextraction with liquid electron...

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Microfluidics

Background:

• Direct coupling of Solid-Phase Microextraction (SPME) to Mass Spectrometry (MS) is widely used for small molecule determination.
• Existing methods often require chromatographic separation, increasing analysis time and complexity.
• There is a need for faster, more sensitive analytical techniques for complex biological samples.

Purpose of the Study:

• To develop and validate a modified microfluidic open interface (MOI) combined with a passive flow-splitter (PFS) for direct SPME-MS coupling.
• To enable rapid and sensitive analysis of small molecules in biological matrices using Liquid-Electron Ionization tandem Mass Spectrometry (LEI-MS/MS).
• To assess the performance of the new interface in terms of speed, sensitivity, and precision.

Main Methods:

• A novel MOI-PFS configuration was developed for direct coupling of SPME to LEI-MS/MS.
• Analysis involved direct immersion SPME (3 min extraction) followed by rapid desorption (1 min) into a microfluidic chamber.
• A passive flow splitter directed a fraction of the sample to the LEI-MS/MS interface for analysis.

Main Results:

• The MOI-PFS configuration significantly improved sample transfer, enhancing signal-to-noise ratio and peak shape.
• Fentanyl, as a model compound, was analyzed in water and blood serum with high sensitivity (LOQs in the µg·L⁻¹ range).
• The entire analytical process, including extraction, desorption, and analysis, was completed in approximately 5 minutes.

Conclusions:

• The developed MOI-PFS-LEI-MS/MS system provides a fast, sensitive, and precise method for analyzing small molecules in complex biological samples.
• The direct coupling approach eliminates the need for chromatographic separation, streamlining the analytical workflow.
• The technique demonstrates a limited environmental impact, aligning with green analytical chemistry principles.