2-propanol dependent RNA absorbance.

RNA absorbances Ad were determined by bichromatic spectrophotometry at 240, 260 and 280 nm, versus 350 nm values, on paper disks containing different 2-propanol concentrations and NaCl amounts. No significant differences in terms of the NaCl content could be observed at alcohol concentrations higher than 70%; the maximum Ad value was found to correspond to about 50% 2-propanol. The possible phenomena implied in the absorbance changes are discussed taking into account the peculiar action of 2-propanol on the water structure and content in the bulk phase within the paper capillaries and inside the macromolecular and aggregation structures of RNA and cellulose.