Optical Rotation
• The degree (angle) of rotation is measured
using a polarimeter and has a specific value
for each optically active substance
• If the rotation is to the right (clockwise),
the substance is dextrorotatory, (+) or (d)
(Latin: dexter, right)
• If the rotation is to the left (counterclockwise),
the substance is levorotatory, (-) or (l)
(Latin: laevus, left)