Quantitative 13C NMR method using the DEPT pulse sequence for the detection of olive oil adulteration with soybean oil
✍ Scribed by Giovanna Vlahov
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 215 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
The polarization transfer method DEPT (distortionless enhancement by polarization transfer) was employed to set up a quantitative method to detect olive oil adulteration by seed oils, in particular soybean oil. The DEPT pulse sequence promotes the transfer of polarization from "concentrate spins = 1HÏ to "dilute spins = 13CÏ via scalar coupling interaction. This improves the signal-to-noise ratios in the 13C NMR spectra which would have to be acquired for quantitative purposes, under conditions of NOE suppression that reduce dramatically the carbon-13 resonance intensities. The resonance intensities of unsaturated carbons, C-9 for oleyl and C-10 for linoleyl and linolenyl chains, were used to detect olive oil adulteration by addition of soya oil at di †erent levels. Calibration graphs based on a linear relationship between resonance intensities and soybean oil concentration were obtained. The limits of detection of the method were determined for each acyl chain. 1997