NMR Service

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NMR Service

• What equipment do we have?
• What can it do?
• How do you get to use it?
• Where can you find it?
• Other stuff you need to know.

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What Equipment do we have?

• Bruker AC200
• What can it do?
• Open-Access instrument with Sample Changer
• 1H at 200MHz, 13C at 50.3MHz
• 1H, 13C and DEPT, routine work only
• How do you get to use it?
• User operated - Very easy - 10min training
• No booking - first come, first served

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What Equipment do we have?

• Bruker DPX400
• What can it do?
• 1H at 400MHz, 13C at 100.6MHz, etc, etc
• Multinuclear, 2D, Pulsed Field Gradients
• Variable Temperature, Non-routine work
• How do you get to use it?
• Operator instrument
• Job Request Forms
• Time is bookable

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Where can you find it?

• Ground floor
• Spur building

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Where can you find it?

• AC200 in G21 (left)
• DPX400 in G20 (right)

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NMR Service Charges

• Your supervisor pays a real money fee for every
  NMR Job done.
• Each Job done on the AC200 costs 1.
• Each Job done on the DPX400 costs 1.
• The money pays for the running costs of the NMR
  service, e.g. cryogens, paper, repairs, etc.

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What else do you need to know?

• AC200 Training
• Done by me when you bring your first sample
• Takes about 10-15 minutes.
• NMR Work Request Form
• Required for all DPX400 work.
• Makes sure your work is not forgotten.
• You must provide a sample or make a booking.
• NMR Data Archive
• Everything is kept forever, so that you may
  reprint data yourself.
• How to Prepare NMR Samples
• Leaflet - PLEASE READ IT!

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NMR Work Request Form

• Identifies you and your sample.
• Describes your sample (Quantity, structure,
  solvent, hazards).
• Outlines the work you want done, or the
  information you need from the spectra.

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NMR Work Request Form
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NMR Work Request Form
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NMR Data Archive

• All data is archived and kept for ever so that
  you can do expansions and reprints for theses,
  papers and posters.
• Data is always available by FTP from our own
  server.
• It is stored in folders by years, months and
  finally by user. Each instrument has its own
  archive.
• Dozens of people use the NMR service, hundreds if
  you look back over the years.
• So that you should always be able to find your
  data, we enforce a strict data naming convention.

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Data Naming Convention

• User Code
• Given to you when you register
• Three letters, or two letters and a number
• Nucleus
• Element symbol H, C, B, P, etc
• Sample Code
• Up to four characters, your choice, A-Z, 0-9
• No lower case (a-z) or punctuation marks
• Dont include your initials, or EXP or RN
• Extension or expno - experiment number
• Added by the system to indicate the type of work

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Data Naming Convention

• AC200 File Name
• aaabcccc.ddd

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Data Naming Convention

• AC200 File Name
• aaabcccc.ddd

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Data Naming Convention

• AC200 File Name
• aaabcccc.ddd

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Data Naming Convention

• AC200 File Name
• aaabcccc.ddd

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Data Naming Convention

• AC200 File Name
• aaabcccc.ddd

ASBH456.001(AC200)
asbh456a 1 1(DPX400)
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NMR Data Archive

• Machine address dava.eps.hw.ac.uk
• 137.195.16.82
• Login name nmrftp
• Password nmrftp
• Path / - the
  top level

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How to Prepare Samples for NMR

• In NMR, unlike other types of spectroscopy, the
  quality of the sample has a profound effect on
  the quality of the resulting spectrum.
• If you follow a few simple rules, the sample you
  prepare will give a spectrum in which useful
  information is not lost or obscured.

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Use the Correct Quantity of Material

• For 1H spectra of organic compounds (except
  polymers) the quantity of material required is
  about 5 to 25mg.
• 13C is six thousand times less sensitive than 1H.
  If you can dissolve about 0.2 to 0.3 millimole
  in 0.7ml, the spectrum will take no more than
  about half an hour to record on the AC200.
• On the DPX400, 0.1 millimole gives a fair 13C
  spectrum after less than an hour.

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Signal-to-Noise Ratio

• S/N
• S/N ? ?NS
• S/N ? m
• Where NS number of scans, m number of moles
  of sample

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So How Long Will it Take?

• NS Time Relative S/N 256 15
  min. 1
• 1,000 1 hr (over lunch) 2
• 4,000 4 hr (half day) 4
• 16,000 16 hr (overnight) 8
• 64,000 64 hr (all weekend) 16
• NS number of scans for a standard 1H-decoupled
  13C spectrum.For other experiments, compare
  relative times only.

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Remove All Solid Particles

• Solid particles distort the magnetic field
  homogeneity because the magnetic susceptibility
  of a particle is different from that of the
  solution.
• You must remove solid particles from your
  samples.
• Filter ALL solutions into the NMR tube through a
  small plug of glass wool tightly packed into a
  Pasteur pipette.

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Make Samples to the Correct Depth

• In the magnet, the main field direction is
  vertical, along the length of the sample. Each
  end of the sample causes a major distortion of
  the field homogeneity which is corrected using
  the spectrometers shim controls
• A partial correction is done for every sample,
  and takes a few minutes. A complete correction
  takes many hours using a high quality test
  sample.
• Your samples must be prepared so that they
  physically resemble the test sample so, after
  filtration, they must be made up to a similar
  depth. This must be between 5cm and 5.5cm, and
  requires about 0.6 to 0.7ml solvent.
• Shorter samples are very difficult to shim, and
  cause considerable delay in recording the
  spectrum. Samples that are too long are also
  difficult to shim and are a waste of costly
  solvent

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Clean your NMR Tubes!

• This cleaning device is cheap and easy to set up
  and use.
• Use pipecleaner for stubborn stains.
• Dry tubes with a blast of dry nitrogen or air.
• NEVER dry tubes in an oven - it doesnt work and
  tubes may distort in the heat.
• Dont forget to clean the tube caps too!

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Damaged NMR Tubes
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Mend Damaged NMR Tubes
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Good Sample Containers
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Bad Sample Containers
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Things We Love To Hear!

• 1. Its 100 pure, only one spot on TLC.
• 2. What exactly is broad-band decoupling / COSY /
  VT /etc?
• 3. Do you think you could get it to run me off a
  few integrals?
• 4. Well, it dissolved perfectly OK in the
  chloroform in the lab.
• 5. Could I book a few days for some VT work?
• 6. I dont think I actually know what you mean by
  overwrite.
• 7. Dont be silly, of course theres a signal
  there.
• 8. What do you mean by an expansion?
• 9. Why have you changed the signal-to-noise ratio
  of this spectrum?

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Things We Love To Hear!

• 10. The coupling from H1 to H2 is 4.93 Hz, but
  the coupling from H2 to H1 is only 4.20 Hz.
• 11. Oh, thats the solvent is it?
• 12. You remember that sample you did for me,
  about two weeks ago?
• 13. Gosh, that did take a long time! Actually,
  Ive got loads more of this stuff if youd like
  it.
• 14. Could you plot this out as a DEPT please?
• 15. Could you do a DEPT for me on this 1H
  spectrum, please?
• 16. Id like a DEPT just over this small region
  here please.

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And Finally...

• Dr Alan Boyd
• Room G20
• a.s.f.boyd_at_hw.ac.uk
• Ext. 3214
• 0131-451 3214

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