項目八：常規(guī)物理常數(shù)與性能分析任務六：旋光度的測定旋光度產(chǎn)生原因及測定意義課程：工業(yè)分析中文Scenario8:PhysicalconstantsandperformancetestingTask6:DeterminationofopticalrotationThecausesandmeasurementsignificanceofopticalrotationCourse:IndustrialAnalysisEglish

一、旋光度產(chǎn)生原因1、光的振動光在傳播過程中向各個方法振動中文一、ThecausesofopticalrotationLightvibratesinvariouswaysduringpropagation1.ThevibrationoflightEglish2、偏振光的產(chǎn)生偏振光:當把自然光通過某種介質(zhì)后，在垂直于光傳播方向的平面上，只在一個特定的方向上振動的光中文2.ThegenerationofpolarizedlightPolarizedlight:LightthatvibratesinaspecificdirectiononaplaneperpendiculartothedirectionoflightpropagationwhennaturallightpassesthroughacertainmediumPolarizingmirrorAnalyzerEglish

3、不對稱碳原子化合物的認識

H

︱R－C－R′

︱CH3不對稱碳原子手性碳原子具有旋光性中文

3.Understandingasymmetriccarbonatomcompounds

H

︱R－C－R′

︱CH3asymmetriccarbonatomchiralcarbonatomHavingopticalrotationEglish

4、基本概念

旋光性：偏振光通過具有手性異構(gòu)的化合物溶液時，使偏振光的振動方向發(fā)生旋轉(zhuǎn)的特性。

旋光度：偏振光通過旋光性物質(zhì)之后，振動方向旋轉(zhuǎn)的角度稱為旋光度。

右旋體：能使偏振光的振動方向向右旋轉(zhuǎn)的旋光性物質(zhì)。

左旋體：能使偏振光的振動方向向左旋轉(zhuǎn)的旋光性物質(zhì)。中文

4.BasicconceptsOpticalactivity:Thecharacteristicofpolarizedlightrotatinginthedirectionofvibrationwhenitpassesthroughasolutionofcompoundswithchiralisomers.Opticalrotation:Theangleatwhichpolarizedlightrotatesinthedirectionofvibrationafterpassingthroughaopticallyactivesubstance.Right-handedbody:arotationalsubstancethatcanrotatethedirectionofpolaLeft-handedbody:arotationalsubstancethatcanrotatethevibrationdirectionofpolarizedlighttotheleft.Eglish

旋光度的大小主要決定于旋光性物質(zhì)的分子結(jié)構(gòu)，不同結(jié)構(gòu)的物質(zhì)對光的旋轉(zhuǎn)能力是不一樣的，另外物質(zhì)使光旋轉(zhuǎn)的角度也與溶液的濃度、液層厚度、入射偏振光的波長及測定時的溫度等因素有關。因此旋光儀測定的旋光度并非特征物理常數(shù)，同一化合物測得的旋光度就有不同的值。因此，為了比較不同物質(zhì)的旋光性能，提出了比旋光度的概念。中文

Themagnitudeofopticalrotationismainlydeterminedbythemolecularstructureofopticallyactivesubstances.Substanceswithdifferentstructureshavedifferentabilitiestorotatelight.Inaddition,theangleatwhichlightrotatesbysubstancesisalsorelatedtofactorssuchastheconcentrationofthesolution,thethicknessoftheliquidlayer,thewavelengthofincidentpolarizedlight,andthetemperatureduringmeasurement.Therefore,theopticalrotationmeasuredbyapolarimeterisnotacharacteristicphysicalconstant,andtheopticalrotationmeasuredbythesamecompoundhasdifferentvalues.Therefore,inordertocomparetheopticalrotationperformanceofdifferentsubstances,theconceptofspecificrotationwasproposed.Eglish

比旋光度一般規(guī)定以黃色鈉光D線為光源，在20℃時，偏振光透過濃度為1g/mL、液層厚度為1dm旋光性物質(zhì)的溶液時的旋光度，叫做比旋光度，用表示

純液體的比旋光度溶液的比旋光度旋光度液體密度液體厚度溶液濃度中文

SpecificrotationTheopticalrotationgeneratedwhenpolarizedlightpassesthroughasolutionwithaconcentrationof1g/mLandaliquidlayerthicknessof1dmatatemperatureof20℃usingayellowsodiumlightD-lineasthelightsourceiscalledspecificrotationandisrepresentedby

SpecificrotationofpureliquidsSpecificrotationofsolution

opticalrotationLiquiddensityliquidlayerthicknesssolutionconcentrationEglish

二、測定意義1、定性鑒別：利用比旋光度例：稱取一純糖試樣10.00g，用水溶解后，稀釋為50.00mL。20℃時，用1dm旋光管，以黃色鈉光測得旋光度為+13.3o。測得值與文獻值對照，此糖為蔗糖中文

二、Determinationofsignificance1.Qualitativeidentification:usingspecificrotationExample:Weigh10.00

gofapuresugarsample,dissolveitinwater,anddiluteto50.00

mL.At20℃,theopticalrotationwasmeasuredtobe+13.3ousinga1dmrotarytubeandyellowsodiumlight.Themeasuredvalueiscomparedwiththeliteraturevalue,andthissugarissucrose

Eglish

2、純度或濃度測定例:稱取蔗糖試樣5.000g，用水溶解后，稀釋為50.00mL，20℃時，用2dm旋光管，黃色鈉光測得旋光度為+12.0o，試求蔗糖的純度。已知蔗糖比旋光度為+66.50解（1）求試樣溶液中蔗糖的濃度C中文

2、PurityorconcentrationdeterminationExample:Weigh5.000

gofsucrosesample,dissolveitinwateranddiluteitto50.00

mL.At20℃,usea2dmopticaltubeandyellowsodiumlighttomeasuretheopticalrotationas+12.0o.Trytodeterminethepurityofsucrose.Known