1. http://antoine. frostburg. edu/chem/senese/101/matter/slides/sld006

2. http://antoine. frostburg. edu/chem/senese/101/matter/slides/sld008

3. Distribution Constant
Equilibrium constant
Also called the partition coefficient K
K = [A]s/[A]m (the ratio of the concentration of a component in the stationary phase to the concentration of that component in the mobile phase)

4. Selectivity Factor α (alpha)
Alpha is a measure of how well two components in a mixture will separate
α = KB/KA
By definition, component B is the component with a higher K ; therefore B prefers the stationary phase over A and will be eluted with a longer retention time. Due to this α will always be greater than 1

5. http://antoine. frostburg. edu/chem/senese/101/matter/slides/sld009

7. Electron Ionization Quadropole Detector Molecule + e- molecule+ + 2e-
Four electromagnetic poles
Rapidly oscillating field
If mass of ion and frequency of oscillation are comparable then the ion will oscillate towards the detector and be measured
A certain mass range can be selected depending on the pole diameter
Quadropole Detector

8. Secondary Ion Mass Spectrometry- + e-
10 ion
20 particles
Ga+
Static SIMS = < 1 x 1013 ions/cm2

9. Time-of-Flight Detection Scheme
Field Free Region +V M+
MCP
detector -V
Sample
e = charge on an electron
1.6 x C
t = time for ion to reach detector
m = mass
v = velocity
V = stage voltage
d = length of field free region
V = voltage of detector

10. TOF-SIMS Molecule-Specific Imaging
Ion Gun x y
m/z, +ions
total ion image
570 µm x 570 µm
Intensity
Si+
Ag+
Cu+
copper grid affixed to silicon substrate with silver paste
molecule-specific image
Just as Si, Cu, and Ag have specific masses so do lipids as shown here
Cu+
Si+

11. TOF-SIMS Identification of Plasma Membrane Lipids
DPPC – dipalmitoylphosphatidylcholine + -
m/z 184
+2H *
m/z 552
m/z 735 (M+H)+
m/z 369
cholesterol
m/z 385 (M-H)+

12. TOF-SIMS Allows for Chemical Identification of Lipid Domains
cholesterol
m/z 369 (M-OH)+
molecular ion m/z 385
DPPC
tailgroup PC
DPPC (M+H)+ + -
m/z 184
m/z 552
+2H
molecular ion m/z 735 Au
370 µm x 370 µm
Ipon further inspection we know that these is DPPC in the cholesterol areas
A. G. Sostarecz; C. M. McQuaw et. al. J. Am. Chem. Soc