Overview of Instrumentation

NMR spectrometers

• Bruker AXR 500 MHz high-field NMR spectrometer with multi nuclear observation capability for routine measurement of standard nuclei (²H, ¹³C, ¹⁵N, ³¹P, & ¹⁹F) and other nuclei as needed.
  • The Bruker is normally fitted with a direct detection liquid probe making it best suited for rapid acquisition of 1D experiments
  • The Bruker also has magic angle solid state (MAS) capability for running solid samples.
• Varian UNITY INOVA 500 MHz high-field NMR spectrometer with multi nuclear observation capability for routine measurement of standard nuclei (²H, ¹³C, ¹⁵N, ³¹P, & ¹⁹F) and other nuclei as needed. This NMR is ideally suited for performing 2-dimensional and more complicated NMR experiments.
  • The Varian has pulsed field gradient (PFG) capability, and is generally fitted with an inverse detection probe providing multidimensional capability. The PFG allows
    • Use of programs such as "Watergate" to render water invisible permitting acquisitions in H2O instead of D2O as solvent.
    • Rapid field recovery in multidimensional experiments cutting acquisition times in half.
• Experiments in the following modes: INEPT, DEPT, COSY, 2DJ, TOCSY, NOESY, ROESY, EXSY, HMQC, and HMBC (providing the requisite tools for structure elucidation)
• The pre-acquisition delay (PAD) macro on the Varian allows a reaction to be followed in situ and array the resulting spectra to show the rate of product growth. More rigorous kinetics macros such as DOSY are also available on the Varian.
• The UVM NMR facility has the capability to tune, match, and observe the following isotopes: ¹H, ²H, ⁷Li, ¹¹B, ¹³C, ¹⁴N, ¹⁵N, 17O, ¹⁹F, ²⁷Al, ²⁹Si, ³¹P, ⁴⁷Ti, ⁵¹V, ⁷⁹Br, ⁸¹Br, ⁸⁷Rb, ⁹¹Zr, ⁹⁷Mo, ¹⁰⁹Ag, ¹¹⁹Sn, ¹²⁹Ze, & ¹⁹⁵Pt.
• Dual alumina columns are used to lower the dew point of air to -72 °C facilitating low temperature operation of both the Bruker and Varian platforms in dynamic NMR studies.

Mass spectrometers

• An Applied Biosystems 4000QTrap Pro high performance hybrid triple-quadrupole/linear ion trap liquid chromatograph-mass spectrometer (LCMS) with collision induced dissociation (CID) capability for MS/MS and for MSⁿ using the ion trap. The ABI 4000QTrap has both the scanning functions of a triple quadrupole with the scanning functions of a linear ion trap that can perform simultaneously in both modes within a single injection/analysis automatically through the software.
• Other features include:
  • Operation in both negative and positive ion mode
  • mass range of m/z = 5 to 2,800 in Q1 and Q3 in RF/DC mode and m/z = 70 to 2,800 in linear ion trap mode
  • maximum scan speed of 2,400 amu/sec in RF/DC mode and user-settable scan speeds of 250 amu/sec, 1000 amu/sec and 4,000 amu/sec in linear ion trap mode
  • A number of operational modes are available, including product ion scanning for structural elucidation and precursor ion and neutral loss scanning
  • Three modes of LC spray ionization: (i) atmospheric pressure chemical ionization (APCI), (ii) "Turbo IonSpray", i.e. ESI, and (iii) Nanospray ESI
  • The LC interfaced to the 4000QTrap a Shimadzu with nano-LC capability
  • A full suite of instrument control and data processing software are available
• Varian Saturn 2100T gas chromatograph-mass spectrometer (GCMS) with a Varian 3900 GC and CP-8400 autosampler
  • The GCMS is an ion trap with a m/z = 10-650 mass range
  • The ion trap operates in electron impact ionization (EI) and postive chemical ionization (PCI) modes
  • Especially useful in PCI mode is the collisionally induced dissociation (CID) option to acquire MS/MS spectra
  • The GCMS is primarily used for automated detection of mixture components and for selected ion monitoring (SIM) for quantitation
• Applied Biosystems Voyager-DE Pro Biospectrometry Workstation matrix assisted laser desorption-time of flight (MALDI-TOF) mass spectrometer located in the Department of Biochemistry. The MALDI-TOF has a 337-nm N₂ 3-ns pulse UV laser, 1.3-m linear flight tube, and a 2.0-m flight tube in "reflectron" mode. The unit can measure both positive and negative ions. In linear mode, it has a ~300-kDa mass range and a resolution of >2000 for small proteins (m/z <20 kDa) and of ~50 for large proteins (m/z ~100 kDa). With the reflector on, the resolution is >7,000 at m/z <6 kDa. Peptide ions are resolved at better than unit resolution with the reflector operating. The TOF has "post-source decay" capabilities.

Electron paramagnetic resonance (EPR) spectrometer

• An E300 Bruker spectrometer for characterization of paramagnetic materials by electron spin resonance (ESR) spectroscopy. The instrument operates at ~9 gHz, commonly referred to an "X-band" and is suitable for work between 77 °K and room temperature. It has variable temperature capabilities and can be used on both liquids and solids.

Fourier-transform infrared spectrometers (FT-IR)

• Perkin-Elmer System 2000 FT-IR spectrometer that will measure solids, liquids and gases using a cell with KBr windows.
• Thermo-Nicolet FT200 FT-IR spectrometer with attenuated total reflectance (ATR) head for solids and liquids.

Also available are UV/visible, fluorescence/phosphorescence and CD spectrometers, an atomic absorption spectrometer, a thermal-gravimetric analysis system, GC and HPLC systems, a magnetic susceptibility balance, an ultracentrifuge, a scintillation counter, and a walk-in cold room.

How do I submit samples for analysis?

NMR:

• Users are first trained by the NMR Facility Manager, P. Bruce Deker, to perform routine 1D NMR spectra of ¹H and ¹³C spectra
• Contact P. Bruce Deker to be trained on use of the NMR instruments. New users must be certified to run the NMR instruments.
• Once trained, use the sign-up sheet in the NMR room (Cook A115) to schedule NMR instrument use. Please review the NMR sign-up guidelines & and operating rules.

Mass spectrometry by GCMS, LCMS or MALDI-TOF:

• Download the sample submission form as an Adobe PDF
  • Fill the form out completely and print. Incomplete forms will result in delays in the analysis.
  • Submit a printed copy of the form to Bruce O'Rourke's mailbox in Cook.
• Place a vial, labeled with your sample ID, containing >1 mg (solids) or >10 μl (liquids) in the box in the cold room on the 3rd floor. Samples are to be submitted in screw-cap vials. For limited sample quantities, V-shaped interior vials (0.5-mL) or Eppendorf centrifuge tubes are preferred. Air sensitive samples should be submitted in a vial with a septum.
• Contact the mass spectrometry facility manager, Bruce O'Rourke, with any questions about your samples, their analysis, or for more information concerning specialized sample analysis
• Can I be trained to use the mass spectrometry instrumentation?
  • In general if you only have one or two samples to be analyzed every now and then, it probably is not worth it the large amount of time that needs to be invested to become proficient enough on any of the mass spectrometers
  • If you have a research project taht will generate a large quantity of samples that can be analyzed in a similar way, contact Bruce O'Rourke for training
  • Generally it is much easier to be trained on the GCMS, then the MALDI-TOF, with the most training required for the LCMS