Identification of novel compounds in rose absolute with gas chromatography/high-resolution mass spectrometry

Abstract

Gas Chromatography/High-Resolution Mass Spectrometry (HRMS) was used to identify new compounds in Rosa damascena and Rosa centifolia absolutes. These compounds were esters derived from the main alcohols of rose absolute (phenylethyl alcohol, geraniol, citronellol, nerol, and (E,E)-farnesol). Based on low-resolution mass spectrometry (LRMS) and HRMS data of rose absolutes, hypotheses were first formulated. In a second stage, the standards of these candidate structures were synthetized and analyzed by LRMS using apolar and polar columns. LRMS spectra of these standards, and apolar and polar retention indices (RI) were compared with those of candidate structures. Only four out of nineteen molecules were validated by these three criteria mostly due to an important difference of polar RIs between the standards and the compounds detected in rose absolutes. In a third stage, absolutes were spiked with synthesized standards and were analyzed by HRMS on both apolar and polar columns to confirm the presence of these candidate structures. Finally, 19 new compounds were identified in Rosa damascena and Rosa centifolia absolutes.