Is Linalyl Anthranilate Indeed Found In Plant Samples? GC-MS Misidentifications in the Scientific Literature.

Area of Science:

• Analytical Chemistry
• Organic Chemistry
• Natural Product Chemistry

Background:

• Linalyl anthranilate (LNA) has been reported in plant extracts and essential oils.
• Previous reports show inconsistent retention behavior compared to NIST database data.
• This discrepancy raises questions about the accuracy of LNA identification in prior studies.

Purpose of the Study:

• To investigate the discrepancies in reported LNA retention behavior.
• To determine if LNA has been misidentified in GC-MS analyses.
• To validate or correct the NIST linear retention index for LNA.

Main Methods:

• Synthesis of pure linalyl anthranilate (LNA) via a novel two-step procedure.
• Authentication of synthesized LNA using Nuclear Magnetic Resonance (NMR) and Gas Chromatography-Mass Spectrometry (GC-MS).
• Determination of LNA retention indices on three common Gas Chromatography (GC) phases (polydimethylsiloxane, 5% diphenyl-95% polydimethylsiloxane, polyethylene glycol).

Main Results:

• Confirmed the accuracy of NIST retention data for LNA.
• Established the linear retention index for LNA on a semi-nonpolar GC column as 2051.
• Observed literature-reported LNA retention indices (1000-1400) significantly differ from validated data, indicating misidentification.

Conclusions:

• Previous reports of LNA in natural samples lack credible evidence.
• The presence of LNA in plant extracts is highly unlikely based on validated retention data.
• Misidentification, particularly of linalyl acetate due to erroneous spectral data in older NIST databases, is the probable cause of false LNA reports.