Enhanced olive oil aroma profiling by solid-phase microextraction (SPME) using the novel approach of multi-step enrichment (MSE®)

Multi-step enrichment (MSE^®) enhances the performance of headspace–SPME–trap (HS– SPME–trap). The aroma profile of olive oil was analysed using GC–MS to identify volatile and semi-volatile organic compounds (VOCs/SVOCs). SPME extraction was performed using an automated multi-mode sample extraction and enrichment platform (Centri^®) containing a sorbent-based focusing trap to retain and preconcentrate analytes. Multiple sequential extractions were loaded onto the same trap from the same vial to produce an enriched sample profile. The technique was used to distinguish between olive oil samples using ChromCompare+, software that transforms complex data into meaningful results.

Introduction

SPME is a solvent-free sample preparation technique in which samples are extracted by immersive or headspace sampling. SPME is used for a wide range of sample classes and applications, including foods and beverages, environmental, clinical, industrial and defence. This is made possible by the availability of a variety of SPME fiber phases (including PDMS, polyacrylate and multi-phase DVB/CAR/PDMS), which allow analyte selectivity to be optimised. However, workflows for conventional (‘direct’) SPME sometimes suffer from its limited sensitivity. This stems from the small volume of sorptive phase on the fiber (typically ~0.5 μL of PDMS), as well as from the relatively slow heating rate of commonly used GC injection ports, resulting in broad peaks.