Chromatography
-
Upload
vanessawhitehawk -
Category
Technology
-
view
128 -
download
2
Transcript of Chromatography
![Page 1: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/1.jpg)
Introduction to Chromatography
Separate a complex mixture into individualComponents based on interactions between a Mobile phase and a stationary phase
Amp = Asp
K = [A]sp / [A]mp
Chromatographic system: column plus detector
Chromatogram: Plot of Detector Response as a function of elution time
![Page 2: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/2.jpg)
![Page 3: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/3.jpg)
GCLCHPLCTLCSFCICSize ExclusionCZEAffinity
Chromatography: Different Types
http://www.youtube.com/watch?v=08YWhLTjlfo
http://www.youtube.com/watch?v=kz_egMtdnL4
![Page 4: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/4.jpg)
Sp: solidMp: liq or gasEquil btwn ads. state and liq-gas
Adsorption
![Page 5: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/5.jpg)
Partition
Sp: liq on solidMp: liq or gasEquil btwn liq. state and liq-gas
![Page 6: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/6.jpg)
Ion ExchangeSp: ion exch. resinMp: liqElectrostatic attractions
![Page 7: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/7.jpg)
Sp: porous gelMp: liq
Permeation into the gel
Molecular Exclusion
![Page 8: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/8.jpg)
Affinity
Sp: solid with immobilized molecMp: liqSpecific interactions
![Page 9: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/9.jpg)
SFCSp: solidMp: SC fluid
Partition btwn fluid and adsorbent
![Page 10: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/10.jpg)
Describe the separation
tR = retention time
tm = dead time
tR’ = adjusted retention time
![Page 11: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/11.jpg)
k’ = capacity factor
Describes migration rate of a solute
Larger k’, longer the solute is retained
Good values: 1-5
k’ = (tR - tm) / tmk’ = K (Vs/Vm)
Describe the separation
![Page 12: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/12.jpg)
= selectivity factor
How well the column separates 2 species
Larger the number, the greater the sepn btwn the two
Always greater than 1
= KB / KA
= k’B / k’
A
= (tR,B – tm) / (tR,A – tm)
Describe the separation
![Page 13: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/13.jpg)
Efficiency of a Separation
Two Factors1- elution times btwn peaks2- how broad the peaks are
![Page 14: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/14.jpg)
Qualitative
Eddy DiffusionLongitudinal DiffusionRate of Mass Transfer
![Page 15: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/15.jpg)
Eddy Diffusion
Multiple pathsIndependent of flow rateDepends on particle diameter…
![Page 16: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/16.jpg)
Longitudinal DiffusionConcentration gradientsGreater flow less spreadingDepends on Diffusion Coeff….
![Page 17: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/17.jpg)
EquilibrationGreater flow rate more spreadingDepends on Diff. Coeff, stationary phase…
Rate of Mass Transfer
![Page 18: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/18.jpg)
Quantitative Description: N,H,R
Examine Peaks
R = tR / Wavg
R = (tR,2 – tR,1) / Wavg
R > 1.5 is good
![Page 19: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/19.jpg)
Quantitative Description: N,H,R
Number of Theoretical Plates (N)
N = L/H N = 16tR2 / Wb
2
Plate Height (H)
Height equivalent to a theoretical plateSmall value is good
Resolution
RN k
ks
avg
4
1
1
2
'
'
Large - good
![Page 20: Chromatography](https://reader034.fdocuments.in/reader034/viewer/2022042815/5564327fd8b42adb258b4a20/html5/thumbnails/20.jpg)
Van Deemter Equation
H ~ A + B/ + C
H