HomeFacility InfoNMR InstrumentationAV500

AV500

PLEASE READ this document carefully before using the AV500 for the first time!

If you have completed the Bruker automation training, you can use the AV500. If you are new to the facility, please look at the training options here.

The AV500 is located in room B-63 in S.T. Olin Laboratory and is best used for routine one- and two-dimensional spectra on dilute or complex samples. This is a 500 MHz spectrometer equipped with a liquid-nitrogen cooled cryoprobe, so its sensitivity is 2-3 times higher than the Varian INOVA-500 and 5-6 times higher than the AV400. It should be suitable for 1H and 19F spectra on very dilute samples with 0.1+ mg analyte and other nuclei on dilute ones (0.5+ mg). The AV500 is functionally the same as the AV501, except that it can run19F experiments, which the AV501 cannot.

The AV500 has been around since 2015 and was purchased with a NSF:MRI grant.

The main features of the instrument are:

  1. Bruker AVIII HD electronics console
  2. Prodigy BBO broadband cryoprobe.
  3. SampleXpress™ 60-position sample changer
  4. Fully automated operation
  5. IconWeb™ web-based user interface
  6. Sample temperature range: 0 to +130°C. Default temperature is 25°C (298K).

What can it do?

We have the following experiments set up for IconWeb:

  1. 1H experiments:
    • H1-quant: Quantitative 1H (4 scans, 90° excitation, 30 s relaxation delay)
      We recommend this experiment because it combines more-than-good-enough sensitivity on most samples with excellent quantitation across all hydrogen environments.
    • H1: Semi-quantitative 1H (16 scans, 45° excitation, 2 s relaxation delay)
      This experiment sacrifices quantitation (expect aromatic and vinylic hydrogens to integrate lower than they should) for a ~60% increase in sensitivity relative to the quantitative experiment. Since sensitivity is rarely an issue with a cryoprobe, this is not a trade-off we recommend for routine use.
    • H1-WET-1F: 1H with single frequency signal suppression. Used for acquiring spectra in non-deuterated solvents with a single resonance (CHCl3, CH2Cl2, etc.) or for samples in deuterated solvents that contain a single intense, unwanted signal.
    • H1-WET-2F: 1H with two frequency signal suppression. Used for acquiring spectra in non-deuterated solvents with a two resonances (THF, MeOH etc.) or for samples in deuterated solvents that contain two intense, unwanted signals.
    • WATERSUP: 1H in H2O/D2O mixtures. Will suppress the water signal but may also wipe out analyte signals close to the water chemical shift.
    • 1H with 31P decoupling
      Do NOT change parameters! Available by request.
  2. 2D Experiments:
    • 2D gCOSY: 2D experiment that connects coupled protons. It’s very quick (4.5 minutes) and robust, and can help you trace networks of neighboring hydrogens. We highly recommend running one for every new compound.
    • 2D HSQC: 2D experiment that connects hydrogens with the carbons they are attached to. It’s more sensitive than a 1D carbon and provides multiplicity information like a DEPT135. It takes about 5 minutes and should work for most samples with 1+ mg analyte. Please note that you will not see quaternary carbons as well as a few others, like terminal alkynes. Ask us if you have questions.
    • 2D HMBC: 2D experiment that connects hydrogens with neighboring carbons. It’s more sensitive than a 1D carbon and will detect quaternary carbons if they are within three or possibly 4 bonds of a hydrogen. Try it out and we’ll help you with the analysis.
  3. 13C experiments:
    • 10 minute, non-quantitative 13C.
      NOTE: 10 minutes on the cryoprobe is equivalent to 60-90 minutes on a standard probe. Always try a 10-minute experiment before running a longer one.
    • 1 hour, non-quantitative 13C.
      If you need a longer experiment, increase the number of scans on the IconWeb “Add Experiment” page.
    • Quantitative 13C experiments.
      Use the “Cr” versions if you have a paramagnetic relaxation agent in your sample.
  4. 31P experiments:
    • 31P with 1H decoupling
    • 31P without 1H decoupling
  5. 11B experiments:
    • 11B with 1H decoupling
    • 11B without 1H decoupling
  6. H2-lock-coup: 2H spectrum via the lock channel
  7. 19F experiments:
    • Semi-quantitative 19F
      Outstanding sensitivity but there is a strong probe background that shows up between -100 and -220 ppm. If your signal is outside this range, you can exclude the background from your spectrum by adjusting the spectral width (sw) and transmitter frequency (o1p) in the “add experiment” page in IconWeb. The background can also be removed during processing by applying backward linear correction. We’d be happy to show you how. The AV400 has lower sensitivity but much cleaner baseline, so if your sample is concentrated enough that may be a good alternative. Quantitative 19F requires that you adjust acquisition parameters based on your sample. Contact us and we’ll show you how.
  8. 15N, 29Si and other nuclei are also available but not added to users by default. If you need any experiment that is not currently in your experiment list, let us know and we’ll add them if we can.

You can access the AV500 IconWeb interface at https://av500.nmr.chem.cornell.edu (Requires Eduroam from campus and VPN off campus)