Rapid quantitative analysis of suspected fragrance allergens in between commercial essential oils and using attenuated total reflectance-infrared (ATR-IR) spectroscopy

We studied the suspected fragrance allergens citral, geraniol, cinnamyl alcohol, alpha-amyl cinnamaldehyde and 4-allylbenzenes (eugenol, methyl eugenol, acetyl eugenol, estragole, safrole and myristicin), as well as 4-propenylbenzenes (isoeugenol, alpha-asarone and trans-anethole) using two complementary, fast and non-destructive methods: attenuated total reflectance-infrared (ATR-IR) and Raman spectroscopy. We investigated a hierarchical cluster analysis based on the ATR-IR data. The gas chromatography-mass spectrometry (GC-MS) data of nutmeg, ylang, sandalwood, basil, ginger, thyme and fennel essential oils correlates very well with the results of Ward's algorithm. We also used ATR-IR spectroscopy as a rapid method for quantitative analysis of suspected fragrance allergens in commercial essential oils. The method was based on ATR-IR utilizing partial least squares regression. The calibrations were modeled in the characteristic region (citral 1193-1194cm(-1), geraniol 1375-1378cm(-1), cinnamyl alcohol 732-734cm(-1), alpha-amyl cinnamaldehyde 1623-1624cm(-1), estragole 1583-1584cm(-1), eugenol 792-795cm(-1), methyl eugenol 804-807cm(-1), acetyl eugenol 1603-1604cm(-1), isoeugenol 959-963cm(-1), trans-anethole 1282-1283cm(-1), alpha-asarone 1401-1402cm(-1), safrole 1441-1443cm(-1)) for suspected fragrance allergens.