Optical Rotation
R. D. Laboratories, Inc. has a Rudolph Research Analytical Autopol V with six wavelength (365 nm, 405 nm, 436 nm, 546 nm, 584, nm, 633 nm) capability and temperature control from 15°C to 30°C. This premier polarimeter can be used for almost any compendial optical rotation or specific rotation testing. Non-compendial determinations of enantiomers (optical isomers) can also be performed. The Autopol V is one of the most accurate and precise digital polarimeters available. An interesting use for determination of a compound’s rotation is the bioavailability. Some molecules will only be bioavailable if it is either dextrorotatory or levororotatory. This dextrorotatory and levororotatory concept is much like our hands, they are mirror images of each other but cannot be superimposed. Some compounds when measured (a liquid or a dissolved solid) will exhibit no rotation. This in itself can be an important specification. Additionally, some specific rotation measurements are indicative of concentration. It is sometimes used to distinguish “natural” versus “man made” compounds.