Spectroscopic Services

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Spectroscopic Services University of Florida
Department of Chemistry
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• Overview of Mass Spec Services
• Ionization Techniques
• MS Ion Analysis
• Sample Submission
• Results
• Discussion

Sample Introduction Ionization Mass
Analysis Ion Detection/Data Analysis
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Mass Spectrometry

• Dr. Dave Powell
• Director

• Dr. Cris Dancel
• Magnetic Sector
• FTICR
• GC/MS
• EI, CI FAB, ESI

392-8782 CLB 101
392-0566, CLB 101

• Dr. Jodie V. Johnson
• Ion Trap
• HPLC-MS
• MS/MS
• ESI APCI

392-8672, CLB 102
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• Mass Spectrometry Equipment
• Finnigan MAT95Q High Resolution (EI, CI and FAB)
• Thermo Trace DSQ GC Quadrupole MS (EI CI)
• Finnigan LCQ HPLC Quadrupole Ion Trap (ESI
  APCI)
• Bruker BioAPEX II 4.7 Tesla FTICR (ESI)
• Bruker Reflex II MALDI TOF with DE

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• Ionization techniques and how to choose
• Electron Ionization (EI)
• Chemical Ionization (CI)
• Fast Atom Bomdardment (FAB)
• Liquid Secondary Ion Mass Spec (LSIMS)
• Electrospray Ionization (ESI)
• Matrix Assisted Laser Desorption (MALDI)

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Electron Ionization (EI)
M e- M 2e-
Sample must be volatilized at 400 C with a
vapor pressure of (1 x 10-6 torr) Stable vapor
required M? is formed Fragment Pattern is
database searchable
Not good for salts, good for non-polar organics
with short chains, MW lt 500-800
http//ms.mc.vanderbilt.edu/tutorials/ms/2.htm2-3
-2
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Chemical Ionization
CH4 CH4 CH5 CH3
CH5 M MH CH4

• Features
• More gentle less fragmentation
• Only get ions if proton affinity of M gt CH3
• Pseudomolecular ion is formed MH
• Can get cluster ions (M C2H5) and (M C3H5)
• MWlt 800

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Fast Atom Bomdardment (FAB) Liquid Secondary
Ion Mass Spec (LSIMS)
Pseudomolecular ion is formed MH MW up to ca.
1500 Good for Ionic Compounds Can get (MNa) and
(MK)
Must dissolve in a liquid matrix glycerol m-nitr
obenzyl alcohol thioglycerol magic
bullet Matrix Peaks are abundant
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Can Analyze Air Sensitive samples
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Electrospray Tip and Plume
Droplet Evaporation
As the drop evaporates, the charge increases
until the droplet breaks (Rayleigh fission). Each
offspring has 2 of the mass but 15 of the
charge. Eventually get an ionized molecule
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Electrospray Ionization
To MS
Provided by ThermoFinnigan
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• Electrospray Ionization (ESI)
• Soluble in solvent (water, methanol, ACN, MeCl2)
• Avoid DMSO and DMF
• Pseudomolecular ion is formed MH
• Very Gentle
• MW to megadalton range
• multiple charges
• preformed ions
• can get electrochemical reactions
• often need a basic site

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MALDI Ion Formation
Matrix
Analyte (MH)
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• Matrix Assisted Laser Desorption/Ionization
  (MALDI)
• Soluble in solvent (MeOH , CAN, H2O)
• Avoid DMSO and DMF
• Pseudomolecular ion is formed MH
• Very Gentle
• MW to megadalton range
• Matrix ions below m/z 500
• preformed ions are good
• often need a basic site

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Mass Spectrometry Fees per sample
Low Resolution (EI, CI, or LSIMS 15   High
Resolution (EI, CI, or LSIMS) 25 GC/MS (EI or
CI)  25 MALDI 35 FT-ICR MS 35  Finnigan LCQ
(ESI or APCI) 30 Direct Infusion MS and
MS/MS  Finnigan LCQ (ESI or APCI) 50
HPLC/MS and MS/MS
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Mass Spec Analysis Request Form Available on
Website Data Results Hard Copy for MAT95, FTICR
and MALDI. Hardcopy and computer files for GC/MS
and LC/MS Which Ionization Technique (Low
Resolution or High Resolution)? Low resolution
mass accuracy 0.3 Da, Is compound present? High
Resolution mass accuracy 5 ppm empirical
formula decreasing utility at higher
m/z, needed by some journals to report novel
compounds
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Tutorial Links http//ms.mc.vanderbilt.edu/tutori
als/ms/2.htm2-3-2 http//wunmr.wustl.edu/7Emsf/i
onmethd.html http//www.asms.org/whatisms/index.ht
ml Fragment Lost Link http//www.chem.uni-potsda
m.de/tools/index.html Free Software http//www.a
cdlabs.com/ Resources http//webbook.nist.gov/ch
emistry/mw-ser.html http//www.spectroscopynow.com
/Spy/basehtml/SpyH/
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More information is better Dont skimp
here!!!! Talk is cheap and easy We dont bite.
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Samples are not run in strict order as
received Turn-around time averages lt3 days
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Note Matrix peaks from FAB/LSIMS may be present
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Data Results for High Resolution
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