Submitted to: Subtropical Technology Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: October 15, 2004
Publication Date: October 21, 2004
Citation: Manthey, J.A. 2004. Ftir analysis of orange oil residues. Subtropical Technology Conference Proceedings. 55:28. Technical Abstract: Orange oil residues have become the focus of large-scale polymethoxylated flavone recoveries. These residues contain the nonvolatile constituents in orange oil, including waxes, flavonoids (primarily the polymethoxylated flavones), phytosterols, and conjugated unsaturated fatty acids. In spite of earlier analyses of these compounds in orange oil, the chemical compositions of orange oil residues are still poorly characterized. In our initial characterization of these oil residues, we found that Fourier Transform Infrared (FTIR) analysis of oil residues provides information about the chemical composition of these materials. Of particular use is the detection and analysis of the polymethoxylated flavones. Infrared absorption bands between 1600-1350 cm-1 are readily assigned to the '(C=C) vibrations of the PMFs. The carbonyl stretch of the PMFs occur at lower frequencies compared to the carbonyl groups of other compounds in the residues. The ether '(O-CH3) and '(O-phenyl) vibrations of the polymethoxylated flavones are evident between 1350 and 1100 cm-1. FTIR measurements of purified PMFs and of residues depleted of PMFs confirm the assignments of absorption bands attributable to the PMfs in orange oil residue. This analytical method will be useful in detecting the presence and relative abundance of the PMFs in orange oil residues.