The paper presents a comparative study regarding the water determination in natural cyclodextrins and
in their essential oil complexes (Apiaceae, Liliaceae, and Cupressaceae families) by using Karl Fischer
titration (KFT) and thermal methods. For the natural cyclodextrins, the influence of the solvent hydrophobicity
and the preheating temperature on the water extraction process were evaluated. The water contents,
estimated by KFT in both methanol and methanol–octanol solvent systems, were 10.6% and
14.4% for a- and b-cyclodextrin, respectively; the water content, estimated by KFT in a more hydrophilic
solvent system, methanol–formamide, was 0.4–0.6% higher. Thermogravimetric evaluation of water conducts
to lower values. For the essential oil/cyclodextrin complexes, the KFT water content were in the
range of 6.4–8.1%, higher values being obtained in the case of Juniperus essential oil/b-cyclodextrin complexes
(7.5–8.1%). With some exceptions, thermal analyses of complexes are in good agreement with the
KFT results.
The paper presents a comparative study regarding the water determination in natural cyclodextrins andin their essential oil complexes (Apiaceae, Liliaceae, and Cupressaceae families) by using Karl Fischertitration (KFT) and thermal methods. For the natural cyclodextrins, the influence of the solvent hydrophobicityand the preheating temperature on the water extraction process were evaluated. The water contents,estimated by KFT in both methanol and methanol–octanol solvent systems, were 10.6% and14.4% for a- and b-cyclodextrin, respectively; the water content, estimated by KFT in a more hydrophilicsolvent system, methanol–formamide, was 0.4–0.6% higher. Thermogravimetric evaluation of water conductsto lower values. For the essential oil/cyclodextrin complexes, the KFT water content were in therange of 6.4–8.1%, higher values being obtained in the case of Juniperus essential oil/b-cyclodextrin complexes(7.5–8.1%). With some exceptions, thermal analyses of complexes are in good agreement with theKFT results.
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