Abstract

FTIR ANALYSIS AND INTERPRETATION OF IR SPECTRA OF FOUR SPICE OILS EXTRACTED BY HYDRODISTILLATION

Esha Tambe* and Sulekha Gotmare

ABSTRACT

FTIR technique is one of the widely used tools for the detection of functional groups in pure compounds and mixtures and for compound comparison. The fingerprinting analysis of essential oils aid the qualitative approach to plant species authentication and quality evaluation. ATR FTIR methods are rapid, inexpensive, non-destructive and have the potential for routine qualitative and quantitative analysis if properly calibrated and validated. In this study, ATR FTIR method was used to determine the functional groups and identify the marker compounds present in the different spice oils. The functional region (4000 – 1500 cm-1) of the FTIR spectra of the spice oils revealed the different functional groups present in the marker compounds whereas the fingerprint region (1500 – 600 cm-1) data assisted to elucidate the structure of marker compounds. Some of the crucial wavenumbers recorded were in the region 3600, 2900, 1700, 1200, 1000 cm-1 and, in case of aromatic compounds, out of plane bending modes below 900 cm-1. In addition to these wavenumbers, overtones were also observed such as Fermi doublet and combination overtone.

Keywords: Marker compounds, Functional group region, Fingerprint region, Fermi Doublet, Authentication and Quality evaluation of oil.