60 MHz1H NMR spectroscopy for the analysis of edible oils.
We report the first results from a new 60 MHz1H nuclear magnetic resonance (NMR) bench-top spectrometer, Pulsar, in a study simulating the adulteration of olive oil with hazelnut oil. There were qualitative differences between spectra from the two oil types. A single internal ratio of two isolated groups of peaks could detect hazelnut oil in olive oil at the level of ∼13%w/w, whereas a whole-spectrum chemometric approach brought the limit of detection down to 11.2%w/w for a set of independent test samples. The Pulsar's performance was compared to that of Fourier transform infrared (FTIR) spectroscopy. The Pulsar delivered comparable sensitivity and improved specificity, making it a superior screening tool. We also mapped NMR onto FTIR spectra using a correlation-matrix approach. Interpretation of this heat-map combined with the established annotations of the NMR spectra suggested a hitherto undocumented feature in the IR spectrum at ∼1130 cm-1, attributable to a double-bond vibration.
School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
T
T
Parker
Oriel College, University of Oxford, Oxford OX1 4EW, UK.
E
E
Limer
Analytical Sciences Unit, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
A D
AD
Watson
Analytical Sciences Unit, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
M
M
Defernez
Oxford Instruments Industrial Analysis, Tubney Woods, Abingdon, Oxford, UK.
D
D
Williamson
Analytical Sciences Unit, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
E Kate
EK
Kemsley
60 MHz 1H NMR; Authenticity; Bench-top NMR; Chemometrics; Double-bond vibration; Edible oil; FTIR; Hazelnut oil; Olive oil; Screening