The most frequently encountered volatile contaminants of essential oils and plant extracts introduced during the isolation procedure: fast and easy profiling

Abstract

Introduction: Unfortunately, contaminants of synthetic/artificial origin are sometimes identified as major constituents of essential oils or plant extracts and considered to be biologically active native plant metabolites.

Objective: To explore the possibility of early recognition and to create a list of some of the most common semi-volatile contaminants of essential oils and plant extracts.

Methodology: Detailed GC and GC-MS analyses of the evaporation residues of six commercially available diethyl ethers and of a plastic bag hydrodistillate were performed. Average mass scans of the total ion chromatogram profiles of the analysed samples were performed.

Results: Almost 200 different compounds, subdivided into two groups, were identified in the analysed samples: (i) compounds that could be only of a synthetic/artificial origin, such as butylated hydroxytoluene and o-phthalic acid esters, i.e. requiring exclusion from the list of identified plant constituents; (ii) compounds possibly of synthetic and/or natural plant origin, i.e. compounds derived from the fatty acid metabolism or products of anaerobic intracellular/microbial fermentation. Average mass scans of the total ion chromatogram profiles provide meaningful and convenient information on uncovering important solvent-derived contamination.

Conclusion: A database of the most common semi-volatile contaminants of essential oils and plant extracts has been generated that provides information on the likelihood of rejection or acceptance of contaminants as possible plant constituents. The suggested average mass scan approach enables fast and easy profiling of solvents, allowing even inexperienced researchers to pinpoint contaminants.