旋光性 EP

旋光度2.2.7.OPTICALROTATION旋光是手性物质的特性，即能使偏振光的平面旋转。Opticalrotationisthepropertydisplayedbychiralsubstancesofrotatingtheplaneofpolarisationofpolarisedlight.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（-）。Opticalrotationisconsideredtobepositive(+)fordextrorotatorysubstances(i.e.thosethatrotatetheplaneofpolarisationinaclockwisedirection)andnegative(−)forlaevorotatorysubstances.精确的旋光度αmλt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 关于同志近三年现实表现材料材料类招标技术评分表图表与交易pdf视力表打印pdf用图表说话 pdf 示。实际操作中，旋光度常用mrad﹒m2﹒kg-1表示。Thespecificopticalrotationαmλtistherotation,expressedinradians(rad),measuredatthetemperaturetandatthewavelengthλgivenbya1mthicknessofliquidorasolutioncontaining1kg/m3ofopticallyactivesubstance.Forpracticalreasonsthespecificopticalrotationαmλtisnormallyexpressedinmilliradiansmetresquaredperkilogram(mrad·m2·kg−1).本药典采用以下常规定义ThePharmacopoeiaadoptsthefollowingconventionaldefinitions.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 快递客服问题件处理详细方法山木方法pdf计算方法pdf华与华方法下载八字理论方法下载 制备。Theangleofopticalrotationofaneatliquidistheangleofrotationα,expressedindegrees(°),oftheplaneofpolarisationatthewavelengthoftheD-lineofsodium(λ=589.3nm)measuredat20°Cusingalayerof1dm;forasolution,themethodofpreparationisprescribedinthemonograph.液体旋光度αD20：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 工程第三方检测合同工程防雷检测合同植筋拉拔检测方案传感器技术课后答案检测机构通用要求培训 液体的密度（g/cm3）计算得出。ThespecificopticalrotationαD20ofaliquidistheangleofrotationα,expressedindegrees(°),oftheplaneofpolarisationatthewavelengthoftheD-lineofsodium(λ=589.3nm)measuredat20°Cintheliquidsubstancetobeexamined,calculatedwithreferencetoalayerof1dmanddividedbythedensityexpressedingramspercubiccentimetre.固体物质的旋光度αD20：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。ThespecificopticalrotationαD20ofasubstanceinsolutionistheangleofrotationα,expressedindegrees(°),oftheplaneofpolarisationatthewavelengthoftheD-lineofsodium(λ=589.3nm)measuredat20°Cinasolutionofthesubstancetobeexaminedandcalculatedwithreferencetoalayerof1dmcontaining1g/mLofthesubstance.Thespecificopticalrotationofasubstanceinsolutionisalwaysexpressedwithreferencetoagivensolventandconcentration.按本药典采用的惯例，旋光度不标注单位；它的实际单位为(°)﹒ml﹒dm-1﹒g-1。IntheconventionalsystemadoptedbythePharmacopoeiathespecificopticalrotationisexpressedbyitsvaluewithoutunits;theactualunits,degreemillilitresperdecimetregram[(°)·ml·dm−1·g−1]areunderstood.本药典的旋光度同国际标准单位旋光度的换算关系如下：TheconversionfactorfromtheInternationalSystemtothePharmacopoeiasystemisthefollowing:αmλt=αλt×0.1745如果专论有特别要求，按要求选择温度（可能不是20℃）和波长。Incertaincasesspecifiedinthemonographtheangleofrotationmaybemeasuredattemperaturesotherthan20°Candatotherwavelengths.旋光计的读数必须精确到0.01°。测量范围通常由鉴定用石英片检查；测量范围内线性由蔗糖溶液检查。Thepolarimetermustbecapableofgivingreadingstothenearest0.01°.Thescaleisusuallycheckedbymeansofcertifiedquartzplates.Thelinearityofthescalemaybecheckedbymeansofsucrosesolutions.方法Method.20±0.5℃下，旋光计调零，用钠光谱的D线（λ＝589.3nm）测定，或者按专论要求的温度测定旋光度。测定液体的旋光度，测定前放入封闭的空测定管，调零；测定固体的旋光度，测定前放入盛有所用溶剂测定管，调零。DeterminethezeroofthepolarimeterandtheangleofrotationofpolarisedlightatthewavelengthofTheD-lineofsodium(λ=589.3nm)at20±0.5°C,unlessotherwiseprescribed.Measurementsmaybecarriedoutatothertemperaturesonlywherethemonographindicatesthetemperaturecorrectiontobemadetothemeasuredopticalrotation.Determinethezerooftheapparatuswiththetubeclosed;forliquidsthezeroisdeterminedwiththetubeemptyandforsolidsfilledwiththeprescribedsolvent按下式计算旋光度：Calculatethespecificopticalrotationusingthefollowingformulae.纯液体旋光度：Forneatliquids:αD20=αl∙ρ20溶液中物质的旋光度：c为浓度，单位g/l。Forsubstancesinsolution:wherecistheconcentrationofthesolutioningramsperlitre.αD20=1000αl∙c按下式计算以g/l为单位的溶解物质的浓度c，或以m/m百分比为单位的浓度c′：Calculatethecontentcingramsperlitreorthecontentc′inpercentm/mofadissolvedsubstanceusingthefollowingformulae:c=1000αl∙αD20c‘=1000αl∙αD20∙ρ20α=20±0.5°C下，旋光度读数，单位度（°）l=测定管长度，单位dm。ρ20=20°C下溶液密度，单位g/cm3,本药典在2.2.5节中以相对密度代替密度。c=溶解物质的浓度，单位g/l。c′=溶解物质的浓度，单位g/l。α=angleofrotationindegreesreadat20±0.5°C;l=lengthindecimetresofthepolarimetertube;ρ20=densityat20°Cingramspercubiccentimetre.ForthepurposesofthePharmacopoeia,densityisreplacedbyrelativedensity(2.2.5).