旋光性 EP.docxVIP

旋光度2.2.7. OPTICAL ROTATION旋光是手性物质的特性，即能使偏振光的平面旋转。Optical rotation is the property displayed by chiral substances of rotating the plane of polarisation of polarised light.右旋物质的旋光度为正的（+），即右旋物质可以使偏振光平面顺时针方向旋转；左旋物质的旋光度为负的（-）。Optical rotation is considered to be positive (+) for dextrorotatory substances (i.e. those that rotate the plane of polarisation in a clockwise direction) and negative (?) for laevorotatory substances.精确的旋光度是指,在温度下，波长为λ的光透过长1m或含1kg/m3旋光活性物质的液体，所发生的旋转，用弧度(rad)表示。实际操作中，旋光度常用mrad﹒m2﹒kg-1表示。The specific optical rotation is the rotation, expressed in radians (rad), measured at the temperature t and at the wavelength λ given by a 1 m thickness of liquid or a solution containing 1 kg/m3 of optically active substance. For practical reasons the specific optical rotation is normally expressed in milliradians metre squared per kilogram (mrad·m2·kg?1).本药典采用以下常规定义The Pharmacopoeia adopts the following conventional definitions.纯液体旋光度α：旋光度α以角度(°)表示，即20℃下，1dm长测定管的纯液体使钠光谱D线（λ＝589.3nm）的偏振光平面所旋转的角度；对于溶液，按专论规定方法制备。The angle of optical rotation of a neat liquid is the angle of rotation α, expressed in degrees (°), of the plane of polarisation at the wavelength of the D-line of sodium (λ = 589.3 nm) measured at 20 °C using a layer of 1 dm; for a solution, the method of preparation is prescribed in the monograph.液体旋光度 ：测定即20℃下，1dm长的测定管的含待测液体的溶液使钠光谱D线（λ＝589.3nm）的偏振光平面所旋转的角度(°)，即溶液旋光度α。溶液中液体旋光度，由溶液旋光度α除以溶液中被检测液体的密度（g/cm3）计算得出。The specific optical rotation of a liquid is the angle of rotation α, expressed in degrees (°), of the plane of polarisation at the wavelength of the D-line of sodium (λ = 589.3 nm) measured at 20 °C in the liquid substance to be examined, calculated with reference to a layer of 1 dm and divided by the density expressed in grams per cubic centimetre.固体物质的旋光度：测定20℃下，1dm长测定管的含被测物质1g/ml的溶液使钠光谱D线（λ＝589.3nm）的偏振光平面所旋转的角度，即溶液旋光度α。溶液中固体物质的旋光度由溶液的旋光度α计算得出。溶液中某物质的旋光度与溶剂和浓度有关。The specific optical rotation of a substance in solution is the angle of rotation α, ex