Ronald P. D’Amelia^1,, Evan H. Kreth¹

Short chain cinnamyl esters hold a multitude of applications within the food, cosmetic and pharmaceutical industries as flavor and fragrance compounds. However, due to high structural similarity, these compounds are difficult to differentiate from one another. Quantitative proton nuclear magnetic resonance (¹H NMR) and Fourier-transform infrared (FTIR) spectroscopies were utilized to not only distinguish between these compounds, but also to quantify their relative concentrations when present simultaneously. ¹H NMR and FTIR spectra were first obtained for each cinnamyl acetate (CA), propionate (CP), and butyrate (CB) individually, followed by those for binary mixtures of weight percent ranging from zero to one hundred percent. Resolved ¹H NMR methyl proton resonances 1.95 (s, 3H), 1.07 (t, 3H), and 0.88 (t, 3H) and unique peaks in the fingerprint region of the FTIR spectra were used to determine relative concentrations of CA, CP, and CB respectively in each of the binary mixtures. Strong, linear correlations were established between gravimetrically achieved weight percent and those ascertained by ¹H NMR (r² > 0.99) and FTIR (r² > 0.98) spectra. These results confirm the use of fundamental spectroscopic techniques ¹H NMR and FTIR in the identification, but more appreciably quantification, of organic compounds.

Proton nuclear magnetic resonance spectroscopy (¹H NMR), Fourier-transform infrared spectroscopy (FTIR), short-chain cinnamyl esters, cinnamyl acetate (CA), cinnamyl propionate (CP), cinnamyl butyrate (CB)