MALDI-TOF Mass? ?? ? ??

1
MALDI-TOF Mass? ?? ? ??
(Matrix Assisted Laser Desorption Ionization
Time Of Flight Mass Spectrometry)
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MALDI ?? ????? ??
Laser
Sample plate

• ?? (A) ? ??? ???? (M) ? ???? MALDI plate? ???.
• ??? ??? ???? ???? ????.
• ?????? ??????? proton transfer ? ?? ????
• MH A ? M AH.

hn
AH
Ground Grid
Variable Grid
20 kV

• ???? ? ??? (organic acid M) ??? ??
• ????? ??? protonation ?? ?? ???? ???, ??? ??
  deprotonation ? ?? ?? ??? ?? ??? ??.
• ???? ???? ???? (A)? ???1 ???, ???-1 ?

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TOF?? ?? ???? ??
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Reflector TOF? ????? ??
Reflector ?? ion mirror ? ???? ???? ??? ??? ????
?? ??? ??(initial energy spread)? ?? ?? ???? ????
?? ???.

• ??? ????? ??? (tube) ??? ??? ??? ? ?? ??? ?? ???
  
• ???(resolution)? ?? ?? ???
• Peptide?? ??? ?? ??? ??? Proteomics ??? ???
• Reflector (ion mirror)? ???? ?? ???? ?? ?? ???
  ??? ?? ? ??
• ? ???(detector) ? ???? ???.
• ? ???? ???? ??? ?? Linear ?? Reflector ??? ???

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DLS SLS ? ??
Center for Supramolecular Nano-Assembly
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DLS (Dynamic Light Scattering)
lt ???? ?? ?? gt
??? ??? ???? ???? ?? ?? ? ???? ?? ?? ?? ????? ???
?? ????? ??? ?? ?? ?? ??? ???? ??? ??? ?? ?? ?,
??? ??? ??? ?? ??? ?? - ??? ?? - ???? ?? ?? - ???
??? ? ? ??
Light intensity at 0
time
Photon detections
lt ?? ?? ?? gt
? I I ?
G(?)
? I ?2
G(?) ?I(t)I(t ?)?
time
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DLS (Dynamic Light Scattering)
?? ??? ????? ??? ?? ?? (?t ) ??? PMT(
photo-multiplier tube )? ???? ???? ?? ??? ?? ???
time auto-correlation function? ???? ??.
G(?) ?n (t, ?t ) n (t?, ?t ) ?
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DLS (Dynamic Light Scattering)
???? ??
g(t) 1 Aexp(-2 Gt), G 1/t) ????? ???
????? (exponential decay rate, G) ? ??
Semilog plot
??? ?? G vs. q2 plot
????? ????? ??? ??
G Dq2
Stokes-Einstein ? ?? (D kT/f, f 6p?Rh)
Rh? ??
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(No Transcript)
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DLS (Dynamic Light Scattering)
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SEM
H2O
THF
TEM
J. Am. Chem. Soc. 2004, 126, 6294. 
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TEM DLS
J. Am. Chem. Soc. 2004, in press
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Zimm Plot vs. Berry Plot
Zimm plot ???, ? 2 ??? ?? ??? ?? ????? ??? ???? ?? ?? (Kc / R(?) vs. sin2(?) kc) Berry plot (square root plot) ? ???? zimm plot??? ?? ?? ???? ??? ??? ?? ?? ?? ? ???? ?? ????? ???. ? ?? berry plot? ?? ((Kc / R(?))1/2 vs. sin2(?) kc)
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Zimm Plot of a PS Standard
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Static Light Scattering in water/THF
Aggregation number 2.18 x 107 g/mol (micelle) /
2,100 (rod-coil) 10,400 Area per
molecule 4?(48.8 nm)2 / 10,400 2.88 nm2 /
molecule Rg/ Rh 48.8/44.2 1.10
Rg/Rh Uniform sphere
0.774 Polymer coil 1.50 Spherical Shell 1.0
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Calculation of Rg
ln(I(q))