Determining the authenticity of methyl salicylate in Gaultheria procumbens L. and Betula lenta L. essential oils using isotope ratio mass spectrometry

The essential oils of wintergreen and birch are composed primarily of methyl salicylate. Because this compound can easily be synthesized, wintergreen and birch oils are frequently adulterated. By using Gas chromatography-combustion/pyrolysis-isotope ratio mass spectrometry (GC-C/P-IRMS) in conjunction with TC/EA-IRMS, GC-FID, GC-MS, and 14 C radiocarbon dating, criteria will be established that can be used to distinguish authentic and natural wintergreen and birch essential oils from adulterated ones or from synthetic methyl salicylate. Commercially purchased samples were compared to both synthetic 'oil of wintergreen' (methyl salicylate) and to natural birch and wintergreen essential oils obtained from trusted sources or from the steam distillation of fresh plant material. δ 2 H VSMOW , δ 13 C VPDB , and δ 18 O VSMOW IRMS results provide a clear distinction between authentic and adulterated essential oil samples.