Practical nuclear magnetic resonance analysis of liquid oil in oilseeds: Ifactors affecting peak width

If proton nuclear magnetic resonance (NMR) spectra of single seeds can be i mproved, a rapid, low-cost method of screening seeds for oil composition co uld be developed for use as a selection tool in plant breeding. NMR spectro scopy was performed on single seeds of borage, flax, and canola to evaluate methods for improving spectra quality (narrowing peak widths and increasin g signal-to-noise ratio) to a degree necessary to measure differences among seeds in a breeding program. Immersion of seeds in a variety of solvents, including deuterated chloroform, deuterated acetone, deuterated dimethyl su lfoxide (DMSO) and completely fluorinated hydrocarbons (FC-77), narrowed pe aks obtained from seeds when compared with spectra from seeds analyzed in t he absence of a solvent. Deuterated chloroform and FC-77 were free of inter fering solvent proton peaks while deuterated acetone and deuterated DMSO co ntributed interfering peaks. The spectra of dehulled seeds had narrower pea k widths than did seeds with hulls. Treatments that decreased seed oil visc osity failed to substantially narrow spectral peak widths of seeds. High ma gnetic field strength did not improve the spectral quality of seeds, as pea k widths increased with field strength. Conversely, low field strength limi ted resolution of oil spectra. Although the 300 MHz spectrum of vegetable o il had greater resolution (narrower peaks) than the 60 MHz spectrum, spectr a of seeds produced at 60 MHz had superior resolution to 300 MHz spectra.