C-13 CPMAS NMR OF BRIGHT AND BURLEY TOBACCOS

C-13 CPMAS NMR spectra were obtained of the leaf laminae and stems of cured bright and burley tobaccos. The solid phase NMR spectra of some of the most abundant tobacco components were also obtained, including cellulose, hemicellulose, and pectin (each isolated from tobacco), cal cium and potassium salts of malic and citric acid, calcium oxalate, ru tin, chlorogenic acid, and nicotine (in the form of a crystalline dita rtrate salt). The tobacco spectra have keen interpreted in light of th ese reference materials, as well as the chemical analyses of similar s amples. Multiple cross-polarization contact times, interrupted decoupl ing, and single-pulse excitation were employed to improve the discrimi nation between overlapping resonances, to reveal new spectral features , and to detect tobacco components obscured by the complexity of the s pectra. These alternative pulse experiments permitted the selective de tection of microscopic calcium oxalate crystals, solanesol and other m obile waxes, nicotine, citrate, and fructose.