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Novel ¹H NMR relaxometry methods to study the proton distribution and water migration properties of tobacco

Zheng, Songjin, Li, Teng, Li, Yuan, Shi, Qunyan, Wu, Fei
Analytical methods 2017 v.9 no.11 pp. 1741-1747
image analysis, manufacturing, nuclear magnetic resonance spectroscopy, oils, quantitative analysis, tobacco, water content
The water and oil distribution in tobacco has a significant impact on its industrial manufacturing. However, the proton distribution in tobacco remains largely unknown. In the present study, the proton distribution in tobacco was measured before and after dehydration. Both the longitudinal (T₁) and transverse (T₂) relaxation times were measured. To distinguish among different water fractions with overlapping signals in the single T₁ and T₂ spectrograms, the T₁–T₂ correlation spectrum was examined. Two water fractions and one oil fraction were firstly proven to exist in tobacco. The migration of water in tobacco, which plays an important role in the efficiency of tobacco processing, was also quantitatively analyzed by spin-echo single point imaging (SE-SPI). The water content in the different layers was determined by the signal intensity of the corresponding layers, and the interlayer and intralayer water migration mechanisms were firstly reported and the corresponding rate was calculated. TD-NMR proved to be an effective method to study tobacco systems.