Direct analysis in real-time high-resolution mass spectrometry as a valuable tool for polyphenols profiling in olive oil

Abstract

A fast and reliable method to characterize the polyphenolic compound profiles in extra virgin olive oil (EVOO) has been developed using direct analysis in real time (DART) and linear ion-trap Orbitrap mass spectrometry (LTQ-Orbitrap-MS). Hydroalcoholic extraction increased speed and reduced matrix effects, and DART-MS/MS ensured accurate analysis. Characterization of polyphenol fingerprinting in EVOO samples takes 2 min. This method exhibited proper linearity (R² ≥ 0.99) in the range of 5–2500 μg g⁻¹, limit of detection (LOD) of 1.5 μg g⁻¹ (signal-to noise S/N = 3), and limits of quantitation (LOQs) of 5 μg g⁻¹ (S/N = 10) for resveratrol (a polyphenol not detected in olive oil). Six spiked levels of this compound in EVOO were evaluated and the recoveries ranged from 75 to 120%. This approach has demonstrated the capability of generating results comparable to LC-MS results with significantly reduced analysis time. The polyphenols identified by DART-MS in 2 min were detected by LC-MS, but in 45 min. These results demonstrated that DART-Orbitrap was a rapid and simple method which could be applied for rapid analysis of polyphenol fingerprinting in EVOO. Principal component analysis (PCA) filtered out the most pertinent data from the MS spectra and classified the EVOO samples, analyzed according to the olive variety.