Hydration of Chlorophyll a
The sorption isothermes and infrared spectra (4000–1000 cm-1) of Chlorophyll a (chl a) are compared.
Between 90 and 10 % relative humidity r.h. 1–2 H2O/chl a is present during desorption. The H2O spectra indicate the presence of two spectroscopically different H2O molecules containing free OH groups and H- bonds of intermediate strength. At low H2O contents (below 1 H2O chl a) H2O interactions are very different and strong H-bonds are formed. This H2O is desorbed only at elevated temperatures (80–100°C). During the subsequent H2O adsorption process water molecules form 2 moderately strong H-bonds with chl a. The changes in H2O interaction are reflected by the spectra of chl a in the C=O streching region as well.
The results are interpreted with respect to a cooperative influence of the magnesium-ion of chl a on the hydration.
KeywordsQuartz Magnesium Ethyl Hydration Acetone
Unable to display preview. Download preview PDF.
- Fong FK (1975). J Amer Chem Soc 97: 689OGoogle Scholar
- Katz JJ, Dougherty RC and Boucher LJ (1966) Infrared and NMR Spectroscopy of Chlorophyll. In: Vernon LP and Seely GR (eds) The Chlorophylls, Academic Press, New York and London, p. 187Google Scholar
- Kleeberg H. This volumeGoogle Scholar
- Kleeberg H, Klein D Luck WAP (1987). J Phys Chem in pressGoogle Scholar