暴走追风
第1楼2009/03/27
It is now common practice to use other light sources, such as xenon or tungsten halogen, with appropriate filters, because these may offer advantages of cost, long life, and broad wavelength emission range, over traditional light sources.
现在,使用其他光源,例如氙或者钨卤素,并使用适当的过滤器已经成为常规操作,因为这些光源与传统光源相比,可以提供在费用、使用寿命、宽波长发射范围等方面的优势。
Specific Rotation— The reference Specific rotation 781S in a monograph signifies that specific rotation is to be calculated from observed optical rotations in the Test solution obtained as directed therein. Unless otherwise directed, measurements of optical rotation are made at 589 nm at 25 . Where a photoelectric polarimeter is used, a single measurement, corrected for the solvent blank, is made. Where a visual polarimeter is employed, the average of no fewer than five determinations, corrected for the reading of the same tube with a solvent blank, is used. Temperature, which applies to the solution or the liquid under test, should be maintained within 0.5 of the stated value. Use the same cell for sample and blank. Maintain the same angular orientation of the cell in each reading. Place the cell so that the light passes through it in the same direction each time. Unless otherwise specified, specific rotation is calculated on the dried basis where Loss on drying is specified in the monograph or on the anhydrous basis where Water is specified.
比旋度:在各论中提到“比旋度<781S>”意味着比旋度的计算将使用该各论中指定的供试液所观察到的旋光度。除非另外指出,旋光度的测量在25 、589nm的条件下进行。如果使用光电旋光计,只需一次测量并以溶剂作空白校正即可。如果旋光计是肉眼观察的,需要至少5次检测取平均值,并以溶剂作校正空白。供试溶液或者液体的温度应该保持在要求数值加减0.5 的范围内。进行样品检测和空白试验时,需使用同一个单元。在每一次读取数据的时候,使该单元保持同样的的成角方位(angular orientation)。放好单元,以便每次光线从同一个角度穿过它。除非另外指出,当该各论中要求干燥失重时,比旋度按干燥品计算,或者当该各论中要求水分时,在按无水计算。
Optical rotation of solutions should be determined within 30 minutes of preparation. In the case of substances known to undergo racemization or mutarotation, care should be taken to standardize the time between adding the solute to the Solvent and introduction of the solution into the polarimeter tube.
溶液的旋光度应该在溶液配制好30分钟内进行测定。对于检测已知具有外消旋或变旋作用的物质,应当小心地采取措施对向溶剂中加入溶质和将溶液加入旋光计管道的间隔时间进行标准化。
Angular Rotation— The reference Angular rotation 781A in a monograph signifies, unless otherwise directed, that the optical rotation of the neat liquid is measured in a 1.0-dm tube at 589 nm at 25 , corrected for the reading of the dry empty tube.
成角旋光:当各论中提到“成角旋光<781A>”,除非有另外的规定,纯液体的旋光是在1.0分米管道、589nm波长、25 条件下检测的,并以干燥空管的读数进行校正。
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* Suitable calibrators are available from the Office of Standard Reference Materials, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, as current lots of Standard Reference Materials, Dextrose and Sucrose. Alternatively, calibration may be checked using a Polarization Reference Standard, which consists of a plate of quartz mounted in a holder perpendicular to the light path. These standards are available, traceable to NIST, from Rudolph Research Analytical, 354 Route 206, Flanders, NJ 07836, or from Rudolph Instruments, Inc., 40 Pier Lane, Fairfield, NJ 07004-2113.
适合的校正设备可以从国立标准和技术研究院标准物质办公室获得。或者,校准可以通过使用一个偏振标准品来进行,该标准品由一片装在垂直于右侧通道的架子上的石英构成。这些标准品可以从以下2处得到,并可追索到国立标准和技术研究院。
Auxiliary Information— Staff Liaison : Antonio Hernandez-Cardoso, B.S., Scientist, Latin American Specialist
Expert Committee : (GC05) General Chapters 05
USP30–NF25 Page 314
Pharmacopeial Forum : Volume No. 27(4) Page 2819
Phone Number : 1-301-816-8308USP30-NF25比旋度《781》