Automated sequential SPME addressing the displacement effect in food samples

Area of Science:

• Analytical Chemistry
• Food Science
• Environmental Science

Background:

• Analyte displacement in solid-phase microextraction (SPME) hinders accurate quantitation, especially for compounds with low affinity to the extraction phase in complex food matrices.
• Hydrophobic compounds and low matrix binding levels exacerbate this displacement effect, impacting the reliability of SPME analysis.

Purpose of the Study:

• To develop and validate an automated sequential SPME-Gas Chromatography-Mass Spectrometry (GC-MS) strategy to mitigate the analyte displacement effect.
• To improve the extraction efficiency of target analytes, particularly polar compounds, in food samples.

Main Methods:

• An automated sequential SPME-GC-MS approach was implemented using two distinct SPME fibers.
• The first step utilized a polydimethylsiloxane (PDMS) coated fiber for extracting hydrophobic interferents.
• The second step employed a divinylbenzene/carboxyl/polydimethylsiloxane (DVB/CAR/PDMS) coated fiber for extracting remaining target analytes.

Main Results:

• The sequential SPME strategy effectively reduced the displacement effect observed in traditional SPME methods.
• Extraction efficiency for target analytes, including 10 key food odorants, was significantly improved, especially for more polar compounds.
• The method was successfully tested on commercial beer samples, demonstrating its practical applicability.

Conclusions:

• Automated sequential SPME is a viable solution for overcoming analyte displacement challenges in food sample analysis.
• This approach enhances the overall extraction efficiency and accuracy for a wider range of analytes.
• The developed method offers improved quantitation of analytes with low affinity to extraction phases in complex matrices.