傅立叶红外光谱介绍课件

傅立叶红外光谱介绍,傅立叶红外光谱介绍,电磁波,Gamma Ray,X-Ray,UV,Infrared,Micro Wave,Short Wave,Radio Waves,Energy eV,Wavenumber cm,-1,Wavelength m,Visible,光与分子的作用,分子激发产生振动,振动的种类,?,伸缩振动,对称伸缩振动,不对称伸缩振动,例如,:,水,变形振动,水的红外图,1500,2000,2500,3000,3500,wavenumber cm-1,60,65,70,75,80,85,90,95,100,Transmission %,正己烷,50,多不同的振动,正己烷,1000,1500,2000,2500,3000,3500,4000,wavenumber cm-1,20,40,60,80,100,Transmission %,C-H stretch,C-H deformation,指纹区“,如何得到一张图,傅立叶变换红外光谱仪,傅利叶变换红外光谱仪原理,光源,动镜,定镜,x,分束器,L,L +,x,x=0,source,Detector,fixed,mirror M1,x,Beam splitter,L,L +,x,x=0,例,1:,x,=0,相长干涉,结果,1. Beam part (,定镜,),2. Beam part (,动镜,),source,Detector,fixed,mirror M1,x,Beam splitter,L,L +,x,x=1/2,例,2:,x,=,1/2,相消性干涉,0,结果,1. Beam part (,定镜,),2. Beam part (,动镜,),source,Detector,fixed,mirror M1,x,Beam splitter,L,L +,x,example 3:,x,=, constructive Interference,0,Resulting signal,1. Beam part (fixed),2. Beam part (movable),x=,source,Detector,fixed,mirror M1,x,Beam splitter,L,L +,x,x=3/2,example 4:,x,=,3/2, destructive Interference,0,Resulting signal,1. Beam part (fixed),2. Beam part (movable),Mirror motion,Intensity,监测器信号,Frequence,Intensity,光源,单色光源,单色光源的调制信号,Entstehung des Interferogramms,Mirror motion,Intensity,Resulting detector signal,Frequence,Intensity,9,条单一频率的光源,Mirror motion,Intensity,总和,:,检测器信号,Frequency,Intensity,红外光源,X, moving mirror,Intensity,干涉图的来源,透射光谱,1.) In the empty sample compartment an Interferogram is detected. The result of the FOURIER transformation is,R(),.,Fourier-Transformation,500,1000,1500,2000,2500,3000,3500,4000,wavenumber cm,-1,0.10,0.20,0.30,0.40,Single channel intensity,X, moving mirror,Detector intensity,2.) A second interferogram is detected with the sample placed in the sample compartment. The result of the FOURIER transformation is,S(),.,S(),shows similarities to the reference spectrum,R(v), but has lower intensities at the regions the sample absorbs radiation.,Fourier-Transformation,500,1000,1500,2000,2500,3000,3500,4000,wavenumber cm,-1,0.10,0.20,0.30,0.40,Single channel intensity,X, moving mirror,Detector intensity,透射光谱,The transmission spectrum,T(),is calculated as the ratio of the sample and reference single channel spectra:,T() = S()/R(),.,500,1000,1500,2000,2500,3000,3500,4000,wavenumber cm,-1,0.10,0.20,0.30,0.40,Single channel intensity,500,1000,1500,2000,2500,3000,3500,4000,wavenumber cm,-1,40,60,80,100,Transmission %,20,ratio,透射光谱,Absorbance Transmission - Why?,1000,2000,3000,4000,5000,6000,Wavenumber cm-1,0,20,40,60,80,100,Transmittance %,1000,2000,3000,4000,5000,6000,Wavenumber cm-1,0.0,0.2,0.4,0.6,0.8,1.0,Absorbance Units,Transmission,Absorbance,T() = S()/R(),Lambert-Beers law:,AB = -log (S()/R(),AB =,c,b,Principle layout of FT-IR spectrometer,Source,Moving,mirror,Fixed mirror,x,Beamsplitter,L,L +,x,x=0,Layout of an FT-IR spectrometer (TENSOR series),Electronic,Source compartment,Sample compartment,Sample position,Detector,Interferometer compartment,Aperture wheel,Filter wheel,Evaluation of IR spectra,定性分析：,1.,鉴定未知物,2.,核对已知物,定量分析,光谱评价,未知物的鉴定,a),通过光谱解析推出分子结构,500,1,000,1,500,2,000,2,500,3,000,3,500,4,000,Wavenumber / cm,-1,40,60,80,100,Transmission %,20,不同有几类分子的红外吸收,烷烃,烯烃,芳香烃,内酯,卤化物,羧酸盐,酸酐,b.),与标准谱库比较,e.g. by using OPUS/Search,未知物的鉴定,identical material = identical IR spectrum,- What you have:,sample,- What you need:,reference library,- What you do:,comparison with reference library,- What you get:,identification,验证已知物,2.) Calculate average spectrum & threshold values,3.) Library structure & validation,1.) Measure reference sample,Wavenumber / cm,-1,Absorbance,Wavenumber / cm,-1,Absorbance,Reference library structure,Identified,sample:,material X,1.) Measure new samples,2.) Compare with library,Identifying new samples,3.) Identify material,- What you have:,sample,- What you need:,calibration set,- What you do:,comparison with calibration set,- What you get:,concentration value,There are two different forms of calibration:,Univariate calibration (OPUS),- Correlates just one piece of spectral information (e.g. peak height or peak area) with the reference values of the calibration set.,Multivariate calibration (OPUS/QUANT),- Correlates considerably more spectral information,- higher degree of precision,- reduced chance of error,OPUS/QUANT uses the Partial Least Squares (PLS) Method.,X,Analysis,1,2,3,4,Absorbance,Concentration,X,1,3,2,4,Absorbance,Wavelength,Calibration,Quantitative evaluation of spectra,2.) Build calibration set (Quant Method),3.) Validate calibration set,1.) Measure calibration spectra,Wavenumber / cm,-1,Absorbance,Setup of a Quant Method,1,2,3,4,Absorbance,Concentration,Concentration:58 vol. %,1.) Measure sample,2.) Compare with calibration set,Determine quantitative results (e.g. concentration values),3.) Result,