Organic Mass Spectrometry at the CRL

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Organic Mass Spectrometry at the CRL

• James McCullagh, 24th Sept 2007

http//www.chem.ox.ac.uk/spectroscopy/
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GCT (GC/MS)
FT-ICR-MS 9.4T
LCT (UPLC/MS
CRL Mass Spectrometry Facility
QTOF-Micro
MALDI micro
LCT Open Access
LCT (LC/MS)
MALDI micro
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How the facility is organised

• Basement research instruments, LC/MS and
  MALDI
• Lower ground floor Trained user LC/MS (prep)
• Ground floor Open access instrument and Acc
  Mass/
• High Res Service (Robin Proctor)
• First floor trained user GC/MS and LC/MS

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Mass spectrometry and why might it be useful for
you

• A mass spectrometer measures the mass to charge
  ratio
• of ions (m/z) providing accurate masses and
  structural
• information from fragmentation products.

Introduces Compound into MS HPLC, GC etc
Sample ionised EI, ESI, MALDI
Data presented as mass spectra
Ions are separated
Ions of different masses counted
3 basic components to a mass spectrometer plus an
inlet and a data acquisition system
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MH
Leucine enkephalin Monoisotopic mass
555.2771 (YGGFL) C28H37N5O7
2MH
MNa
1111.4734 Da 20 compounds at 1ppm
556.2710 Da 2 compounds at 1ppm
Dimer 2MH
MH
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Mass Spectrometer schema
Liquid chromatography
Ultra high pressure Liquid Chromatography
Syringe Pump
Gas chromatography
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Mass Spectrometer schema
Matrix Assisted Laser Desorbtion
Ionisation (MALDI)
Development of ion sources has increased the
scope of MS applications significantly.
Electrospray Ionisation
Electron and Chemical Ionisation
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Electrospray Ionisation soft ionisation

• Atmospheric ionisation very efficient
• Strong electric field applied to a fine spray of
  liquid.
• Very wide range from small of compounds from
  molecules
• to proteins.

Positive Ion Amino, Amide, Ester,
Aldehyde/Ketone, Hydroxyl
Negative Ion Carboxylate, Hydroxyl/phenol, Imide
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Electrospray Ionisation
Efficient ionisation requires the presence of
functional groups with medium-high polarity
Positive e.g. MH, MNH4, MNa
Negative e.g. M-H-, MCl-, MHCO2-
http//www.chem.ox.ac.uk/spectroscopy/
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Mass Spectrometry systems available to staff and
students at the CRL
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Open Access ESI
Measure the sample on the Open Access
Electrospray (ESI)-MS in Lab 20.062 (unless you
know that the compound does not ionise by ESI)
http//www.chem.ox.ac.uk/spectroscopy/
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ESI Measurement

• Open Access Electrospray (ESI)-MS
• Sample preparation Read this carefully!!
• Dissolve the sample in an organic solvent (e.g.
  DCM, CHCl3, EtOAc, MeCN, MeOH) or water at 1
  mg/ml
• Dilute 200-fold in MeOH (if necessary use 5050
  MeOHMeCN (low polarity) or water (high
  polarity))
• Place the solution in a 2 ml sample tube with a
  "snap cap" lid (tubes and caps available from
  stores)

http//www.chem.ox.ac.uk/spectroscopy/
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ESI Measurement Open Access Login

• Login sample on the mass spectrometer PC

http//www.chem.ox.ac.uk/spectroscopy/
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ESI Measurement Login continued

• Pick Supervisors initials from the list
• Job ID generated
• Select Positive or Negative ion mode (or both)
• Number of samples/description
• Tray and vial position is given pay close
  attention!
• Sample will take approximately 2minutes to run
  and a mass spectra will be generated and printed.
• Remove your sample vial from the autosampler
  tray.

http//www.chem.ox.ac.uk/spectroscopy/
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Accurate Mass and High Res Service
2. If ESI measurement is unsuccessful (no
distinct MH etc.) Alternative ionisation
method required Submit 0.5 1 mg of neat
sample together with a completed white form and
failed ESI spectrum, and log the submission on
the white Excel Spreadsheet
http//www.chem.ox.ac.uk/spectroscopy/
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The Service Sample Submission
White Excel Spreadsheet High Resolution MS
Fill in the next available row with your name,
group (select from dropdown menu) and date
(mm/dd/yy). Take the Sample No. and write
on the white form
http//www.chem.ox.ac.uk/spectroscopy/
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The Service Sample Submission
Label sample tube with Sample No. (MSS..) and
place in white sample rack in the fridge
http//www.chem.ox.ac.uk/spectroscopy/
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Sample Submission
Samples will be measured by CI, EI or FI and the
spectra placed in the appropriate tray (usually
takes a few days).
http//www.chem.ox.ac.uk/spectroscopy/
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Sample Submission ESI Accurate Mass
3. If ESI measurement is successful (clear MH
etc. observed) and an accurate mass measurement
is required for elemental composition Submit
existing ESI sample together with a completed
yellow form and low res. ESI spectrum, and log
the submission on the yellow Excel Spreadsheet
http//www.chem.ox.ac.uk/spectroscopy/
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Sample Submission ESI Acc Mass
Yellow Excel Spreadsheet
Fill in the next available row with your name,
group (select from dropdown menu), polarity of
measurement (ve or ve). Take the Sample No.
and write on the yellow form
http//www.chem.ox.ac.uk/spectroscopy/
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Sample Submission - ESI
Label sample tube with Sample No. (ESI..) and
place in yellow sample rack in the Tray
Position indicated on the yellow Excel
Spreadsheet
http//www.chem.ox.ac.uk/spectroscopy/
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Sample Submission - ESI
Samples will be measured by ESI on a high
resolution spectrometer and the elemental
composition data placed in the appropriate tray
(usually next day)
http//www.chem.ox.ac.uk/spectroscopy/
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Trained User Instruments
GC/MS and LC/MS measurements can be performed by
trained users. GC/MS is regularly used
by a number of research groups, and is
particular useful for small, non-polar molecules
which dont ionise well by ESI-MS
http//www.chem.ox.ac.uk/spectroscopy/
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http//chem-booking.chem.ox.ac.uk/booking/
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Trained User Instrument Operation
LC/MS is more specialised and demanding. Training
is only provided if the techniques forms an
integral part of a project
LC/MS Waters 2790/LCT Classic
UPLC/MS Waters UPLC/LCT premier
http//www.chem.ox.ac.uk/spectroscopy/
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Trained User Instruments MALDI
Waters MALDI micro
http//www.chem.ox.ac.uk/spectroscopy/
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Research Instruments ESI-MS/MS and high
resolution
A range of research instruments are available. If
you think you require their use please come and
see myself or Robin Proctor.
Micromass QTOF Micro
Bruker microTOF
http//www.chem.ox.ac.uk/spectroscopy/
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Research Instrument Bruker FT-ICR-MS (APEX Qe)
Extremely high resolution Sub-ppm
mass accuracy High sensitivity
http//www.chem.ox.ac.uk/spectroscopy/
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Waters SYNAPT ion mobility MS
SYNAPT with Triversa nanomate
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Safety issues in mass spectrometry

• Read safety information on website
• No lab coats to be worn in MS labs.
• Open access and ZMD autosampler are often
  continuously in operation. Care should be taken
  when submitting samples.
• MS sources are maintained at 80-250oC and 3Kv,
  always switch out of operate before opening the
  source.

http//www.chem.ox.ac.uk/spectroscopy/
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Information
Make use of the information available on the
Web This presentation will be on the website
soon My office is in the basement next to
NMR, please come and find me if you have any
questions.
Mass spec webpages http//www.chem.ox.ac.uk/spect
roscopy/ Instrument booking
http//chem-booking.chem.ox.ac.uk/booking/