Accurate identification and quantification of ultra-multi-target flavours in essential oils through a combination of retention index distribution-based parallel dual-column GC-MS/MS and analyte protectants

Comprehensively characterising the flavour composition of essential oils (EOs) is critical due to its wide application in food, cosmetics and medicine industries. The present research aims to obtain accurate identification and quantification of 592 flavours in EOs from different plant sources using parallel dual-column gas chromatography-tandem mass spectrometry (GC-MS/MS). A strategy based on retention index distribution was introduced to simplify the optimisation process of separation distribution on the dual columns and elution distribution within the analysis process for analytes. Each analyte was identified as a unique and resolved peak through the complementary separation capacity of dual columns and the specific monitoring ability of the MS/MS transitions. To improve the accuracy of quantitative analysis, a combination of 1,2-octanediol, 1,2-nonanediol, 1,2-tetradecanediol, and phytantriol was used as analyte protectants (APs) for matrix effect compensation. The addition of APs effectively eliminated the differences in the peak response of the same analyte in pure solvent and EO samples from different plant sources. The proposed method demonstrated good linearity with correlation coefficient values above 0.999 for 72.5% analytes, high sensitivity with limit of quantifications below 10 ng/mL for 77.7% analytes, good accuracy with recoveries between 80% and 120% for 97.3% analytes, and high repeatability with relative standard deviations between 0.1% and 10.0% for 96.6% analytes at all three spiked levels. Compared to GC/MS in analysis of marigold, lavender, and fennel oils, this parallel dual-column GC-MS/MS method is a much more reliable and powerful tool for accurately identifying and quantifying ultra-multi-target flavours in EOs, which is critical for fully characterising their flavour composition, precisely controlling the quality of EO materials and further developing a new flavouring technology.