Is Linalyl\nAnthranilate Indeed Found In Plant Samples?\nGC-MS Misidentifications in the Scientific Literature

Linalyl anthranilate (LNA) has been identified in a number\nof plant\nextracts and essential oils by various authors using gas chromatography–mass\nspectrometry (GC-MS). However, the reported retention behavior of\nLNA in these studies is inconsistent with the retention data provided\nin the NIST database. Therefore, the objective of this study was to\ndetermine whether the reports of LNA were the result of misidentifications\nin GC-MS analyses or if the linear NIST retention index was inaccurate.\nTo accomplish this, linalyl anthranilate was synthesized in a two-step\nprocedure, and the resulting product was authenticated using nuclear\nmagnetic resonance (NMR) and GC-MS analyses. This is a new synthetic\nroute to linalyl anthranilate. Subsequently, retention indices for\nlinalyl anthranilate were determined on three commonly used GC phases:\npolydimethylsiloxane, 5% diphenyl–95% polydimethylsiloxane,\nand polyethylene glycol. The study confirmed the accuracy of the NIST\nretention data, establishing the linear retention index data for LNA\non a semi-nonpolar GC column as 2051. However, LNA reported in the\nliterature by various authors exhibited a retention index in the elution\nwindow of approximately 1000–1400, strongly suggesting that\nthese reports were the result of GC-MS misidentifications. A review\nof all reported occurrences of LNA in natural samples found no credible\nevidence of its presence. In many cases, it appears to be a misidentification\nof linalyl acetate caused by the occurrence of an erroneous spectrum\nin the older versions of the NIST mass spectra database.