Supplement_3_Spectrophotometric_Analysis.pdf

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1、Supplement3SpectrophotometricAnalysisPROCEDURE--PartA.•PreparationofStandardSolutions-3#1.Pipet0.00,1.00,2.00,3.00,4.00,5.00mL1.00×10Mphosphatestocksolutioninto1#-650-mLvolumetricflasks,respectively.(AdditionVolumeandconcentrationofphosphateinpreparedsolutions)######sample123456V(mL)0.001.002.003.0

2、04.005.00c(M)##2.Pipet2.00mL2MHNO3solutionintoeach1-650-mLvolumetricflask.##3.Pipet1.00mLoftheammoniumvanadomolybdatestocksolutionintoeach1-650-mLvolumetricflask.4.Dilutethesolutionbyfillingthevolumetricflaskuntilthemeniscusreachthemark.PROCEDURE--PartB.•AdjustingtheSpectrophotometer1.Turnonthespec

3、trometertowarm-up(15min).2.Adjustthewavelenthto400nm.UseablackblocktoadjustT=0%.#3.Washandrinsethecuvettes.Insertacuvettefilledwith¾1blanksolutiontosetT=100%.PROCEDURE--PartC.•MakingtheAbsorbanceSpectrumUsingastandardSolution#1.Rinseanothercuvetteand¾filltherinsedcuvettewiththe6solution.2.Insertthe

4、cuvetteintothespectrometer.MeasureandrecordAin400-450nmevery10nm.3.FindλmaxcorrespondingtothemaximumA.PROCEDURE--PartD.•MakingtheCalibrationCurveUsingthestandardSolutions#1.Rinsethesamecuvette,¾filltherinsedcuvettewiththe2solution.2.Insertthecuvetteintothespectrometer.MeasureandrecordAatλmax.##3.Re

5、peatabovestepfor3-5solutions.•(Alldatapointsforagivencurvemustbemeasuredwiththesamecuvvetteandthesamespectrometer.)PROCEDURE--PartE.•DeterminationofUnknownConcentration1.Pipet5.00mLoftheunknownphosphatesolution,2.00mLHNO3and1.00mLofthe#ammoniumvanadomolybdatesolutioninto750-mLvolumetricflask.2.Dilu

6、tethesolutionbyfillingthevolumetricflaskuntilthemeniscusreachthemark.3.¾filltherinsedcuvettewiththeunknownsolution.UsethespectrometertomeasureA.4.Determinationofunknownconcentrationbyusingthecalibrationcurve.νPleasemakethecurvesbysoftwaressuchasoriginandexcel.