OPTICAL ROTATION
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12 shows the general layout of the optical component of the optical rotation device.
An important feature of optical rotation is that it is thousands of times more sensitive near a spectroscopic absorption band of the substance than at wavelengths removed from it. Such biological molecules as nucleic acids and aromatic amino acids maximally absorb in the 2600 Å and 2800 Å regions, respectively. Organic compounds formed by chemical synthesis generally consist of mixtures which rotate light in opposite directions and thus neutralize each other. It is a characteristic property of living things to select and synthesize forms which rotate polarized light in one direction.
