NMR_instrumentation UVM chemistry

The UVM chemistry department has two high field NMR spectrometers, which are available for use by chemistry faculty, post docs, graduate and undergraduate students doing research in a laboratory. The NMR spectrometers may also be used by researchers from other UVM departments as well as users in the Burlington area. Use of the spectrometers is subject to a “fee-for-service” charge on an hourly basis. If you need spectral analysis assistance or assistance with more involved NMR experiments, there is also an hourly charge for the NMR facility manager’s time.

We use an on-line NMR scheduling system found at https://faces.ccrc.uga.edu/. Once you are trained on one of the spectrometers, an account will be set up for you. Our group name for scheduling is "UVMNMR." Your login will be your NetID, and you will set your own password once the account has been made up.

Please contact the NMR facility manager, Dr. Monika Ivancic, to request training on either of the two NMR spectrometers. Here is a brief description of the instruments along with their available probes:

Bruker Avance III HD 500MHz NMR spectrometer

  • High dynamic range digital console
  • 3 RF channels
  • BLAXH2H300/100/150 transmitter
  • BLAX500 linear broadband amplifier
  • BLAH300 1H/19F linear amplifier
  • HPPR/2 Preamplifier
  • BSMS shim and Digital Lock control, BOSS-3 shim system
  • GRASPTM II gradient spectroscopy
  • BSVT variable temperature control unit
  • ATM automatic tuning and matching
  • Ascend 500/54 magnet with TMC vibration isolators
  • TopSpin 3.2 pl.6 software (CentOS 5.10 Linux)

Available Probes

Dedicated probe: 1. Bruker BBFO+ (SmartProbeTM) 5mm broadband probe with enhanced 1H detection and digital tuning for observation over the range of 15N to 31P and 19F with 1H decoupling.  The Automatic Tuning and Matching (ATM) accessory allows for computer control of tuning and matching of different samples and different detection of nuclei.  The VT range on the BBFO+ probe is from -150⁰C to +150⁰C.

2. Bruker VTN multinuclear double-resonance MAS (Magic Angle Spinning) solid state probe, which incorporates a single coil manually tunable from 15N to 31P, doubly tuned for 1H high power decoupling.  This is a top-loading probe that takes 3.2mm ZrO2 rotors, with an active volume of 10 to 30 L, a maximum spinning speed of 24 kHz, and a VT range from -30⁰C to +80⁰C.

3. Bruker TXI (inverse triple resonance) 5mm probe for 1H observation with both 13C and 15N indirect observation.  The ATM accessory allows for computer control of tuning and matching from sample to sample.

The first probe is typically installed in the spectrometer, while the second and third probes are installed when researchers need them, with at least two to three weeks notice to other users.

Varian Unity Inova 500MHz NMR spectrometer          

  • 3 RF channels with waveform generators
  • 2H-gradient shimming
  • Variable temperature control
  • FTS gas-stream cooler (-20⁰C to +80⁰C)
  • z-axis pulsed field gradients
  • 1D and 2D direct & indirect detection experiments
  • VnmrJ 4.2 software (RedHat 6.2 Linux)

Available probes:

Dedicated probe: 1.  Varian inverse triple resonance HCN 5mm probe that is manually tunable and has Z-only gradients.  Primarily used for one dimensional 1H detection and for two dimensional 1H, 13C or 1H, 15N indirect detection.  The VT range is restricted from -10⁰C to +60⁰C, since N2 gas can’t be used.

2.  Varian PFG Switchable (X/1H) 5mm probe, that can be manually tuned to various nuclei ranging from 15N to 31P.  This probe is only installed if Bruker’s BBFO+ probe needs to be repaired.

UVM’s NMR facility has the capability of acquiring numerous NMR experiments.  The directly detected X-nuclei experiments are acquired on the Bruker 500, and include the following nuclei:  1H, 2H, 7Li, 11B, 13C, 14N, 15N, 17O, 19F, 27Al, 29Si, 31P, 47Ti, 51V, 79Br, 81Br, 87Rb, 91Zr, 97Mo, 109Ag, 119Sn, 129Ze, & 195Pt.  Two dimensional experiments may also be acquired on the Bruker, depending on the length of the experiment and the time of day for acquisition.  During the week, Monday through Friday, 8 a.m.-5 p.m., a maximum of 30 minute time slots are allowed (unless you make prior arrangements with the NMR Facility Manager), while in evenings and on weekends, longer experiments may be acquired.

The Varian NMR is primarily used for simple 1H 1D acquisition and for 1H detected 2D acquisition, such as COSY, TOCSY, NOESY, ROESY, HMQC, and HMBC, needed for resonance assignments and structure elucidation.  For help with setting up these experiments, please schedule a time with Monika Ivancic, the NMR facility manager.  Spectrometer time on the Varian NMR is less restricted, and longer time slots are allowed during the weekday.

COSY data uvm chem

NOESYdata UVM chem

HSQC_data UVM chem
 

HSQC2 UVM Chem

 

For training on the NMR spectrometers or for any special NMR experiments, please contact the NMR facility manager:

Monika Ivancic, PhD
Lab: Discovery W103
Office: Discovery W103A
Office phone: (802) 656-0285
e-mail:  Monika.Ivancic@uvm.edu
mail: Department of Chemistry
82 University Pl.
University of Vermont
Burlington, VT 05405

For all NMR users: please review the NMR facility guidelines and policies.

UVM Department of Chemistry NMR Facility Policies

Incoming graduate students, undergraduates and all first-time users should visit the Department of Chemistry Instrumentation Facility website: http://www.uvm.edu/~chem/?Page=instruments.html for information on the facility and training.

General policies

All users must reserve slots online and sign the instrument log book each time.

If there is a problem, please give a detailed description to help us resolve it in an efficient manner.  If you encounter a problem during business hours, please immediately report it to the manager in person, by email, text or phone.  In case of hardware or software issues, immediately put a note on the NMR instrument to prevent others from potentially worsening the situation until help arrives.

Remember: Prompt reporting of problems may help prevent a minor issue from becoming a major (and very expensive!) one.  Don’t wait for the problem to magically “disappear”: during nights and weekends, call or text the manager’s cell phone immediately for assistance. 

Failure to report problems may result in suspension of your user privileges.

In order to minimize the possibility of NMR tube breakage and to ensure good spectra, only high-quality tubes rated for a 500 MHz instrument are permitted.  “Disposable” quality, “repaired,” chipped, or non-standard NMR tubes are not allowed. Norell S-5-500-7, Norell S-5-500-QTZ-7, Wilmad 528-PP-7 or -8, Wilmad 535-PP-7 or -8, New Era NE-HL5-7 or -8, New Era NE-UL5-7 or -8, New Era NE-HP5-7 or -8, New Era NE-UP5-7 or -8 tubes are rated for 500 MHz spectrometers and may be used. The department stocks standard Wilmad 528-PP-7 tubes for purchase from the stockroom.
NOTE: Do not spin top-heavy screw-capped or J. Young tubes.

Training and instrument access

NMR instruments are accessible to fully-trained individuals with a current user account.  All training must be arranged through the facility manager. Upon successful completion of the training on a specific instrument, the facility manager will create an instrument account, which will also be tied to account billing. Separate training must be completed and a user account created for each of the NMR instruments.

Use of the instruments without manager training is not permitted.  Never allow another user to use your online scheduling or instrument accounts. 

If you feel at all uncertain about proper operation of the instruments, schedule some refresher training with the manager, or ensure that the manager or an experienced user will be available to help you.

The NMR instrument will be unavailable for use during and immediately after liquid nitrogen and liquid helium fills.  While liquid helium fills happen infrequently (every few months), liquid nitrogen fills are done weekly.  LN2 fills are typically done on Wednesday mornings, and will be blocked off on the online reservation system a few days in advance (typically 9 a.m. for the Varian and 9:30 a.m. for the Bruker), and require   about 45 minutes to allow for filling and equilibration of the magnetic field.

While rare, the instruments are subject to interruption in access at any time due to facility or instrument issues.  Unfortunately, the manager may need immediate access to an instrument due to unforeseen circumstances which may impact your experiment or reservation times.  Please be understanding of these situations, and the manager will keep you informed of developments in a timely manner.

Reserving time on the instruments

All reservations for time on either instrument should be made in advance using the Faces scheduling system at faces.ccrc.uga.edu.  Please contact the manager if you need to create an account.

1) Signup rules for the Bruker:
a. “Daytime” reservation blocks are available in 10 minute increments between 8 a.m. and 5 p.m. on weekdays, up to 30 minute maximum consecutive time.
b. Reservations may only be made on the same day of intended usage. 
c. Between 5 p.m. and 8 a.m., longer “overnight” discounted blocks may be reserved. 
d. A long overnight block may not start until 6:30 p.m. or later (check with manager).

2) Signup rules for the Varian:
a. “Daytime” reservation blocks are available in 15 minute increments between 8 a.m. and 5 p.m. on weekdays, for a maximum of four hours.
b. Reservations may be made up to two days in advance without manager approval.
c. Between 5 p.m. and 8 a.m., longer “overnight” discounted blocks may be reserved.

3) Spectroscopist-assisted experiments (e.g. specialty experiments, such as variable-temperature NMR), new user training, and cryogen fills may be scheduled as needed by the manager at least 24 hours ahead of time on either instrument.

4) Booking the “full overnight” slot for either instrument from 6:30 p.m.–8 a.m. requires prior manager approval, and should be scheduled at least 24–48 hours in advance.
a. In order to have at least one instrument available at a time, both instruments cannot be booked for “full overnight” reservations concurrently.

5) All users are accountable for the time that they reserve.  If you find that you cannot make your reserved time for any reason, delete the time slot so that another user may take your time.
a. Past time cannot be deleted (i.e. you cannot delete a 12:00 reservation at 12:02 p.m.).
b. Tip: If you do not know if you will need the full 30 minutes, consider signing up for a block of 20 minutes, and then 10 minutes, and cancelling the latter block as time permits.
c. You can contact the user of a reserved block through the online scheduling utility by clicking on their block of time and typing a message; it will be sent by email.

6) All users are required to sign-in in the logbook at each workstation, indicating times, name, solvent, and nuclei.  Notify the manager promptly in case of a problem.

Note: Failure to comply with signup and usage rules will lead to suspension or termination of user privileges. If you have any questions, please contact the facility manager.
 
Instrument configuration and use

Two complementary probes are installed by default on the NMR instruments to best highlight the strengths of the two  spectrometers; your choice of instrument should reflect the experiment needed. For high-sensitivity heteronuclear experiments such as 13C, 31P, 29Si, 11B and 15N as well as routine 1H acquisition, the Bruker AVANCE III HD 500 Hz NMR with broadband probe should be used.  For high-sensitivity 1H, as well as 2D experiments and chiller-cooled variable temperature NMR (down to -15 °C), the Varian Unity/Inova equipped with an HCN inverse detection probe should be used.  Both the Bruker and Varian are equipped to handle elevated-temperature experiments (the Bruker up to 150⁰C, the Varian up to 60⁰C).  Liquid nitrogen-cooled low-temperature NMR experiments may only be acquired on the Bruker spectrometer.

Looking to run a specific experiment?  Contact the manager for training on heteronuclear or multidimensional NMR experiments, or to have a new experiment configured to fit your needs.

One weekend per month, upon reservation at least one week in advance, the Bruker Avance III HD NMR may be dedicated to solid state NMR. Installation of the solids probe for these weekends will necessitate that the facility manager have access to the instrument typically starting at 2pm on Thursday and until noon the following Monday to reconfigure the instrument.

Data processing and archiving

Currently, data is not archived on an external server. You, the researcher, are responsible for regularly downloading your files from the spectrometers remotely using FTP software, or locally via USB memory key. It is highly recommended that you keep hard copies of your spectra and back up your digital data frequently.

NMR data will be purged periodically. It is the user’s responsibility to archive their own data.

Mass Spectrometer Specifications

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 MS3 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
  • Two modes of LC spray ionization: (i) atmospheric pressure chemical ionization (APCI), and  (ii) "Turbo IonSpray", i.e. ESI
  •  The LC interfaced to the 4000QTrap is a Shimadzu Prominence LC system
  • 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 positive 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

Waters Xevo G2-XS quadrupole time-of flight (QTOF) high resolution LCMS available for high resolution mass-accurate compound molecular weight determinations

  • The Xevo LCMS is in Prof. Matthews' laboratory, but molecular weight determinations are done on samples submitted to the facility (see below)
  • Mass separation by a quadrupole (Q) mass selection of m/z = 20-4000 & 20-16,000 (non-resolving) and time of flight (TOF) m/z = 20-100,000 mass ranges
  • XS CID collision cell
  • TOF high resolution of 40,000 FWHM
  • ESI and nanospray-ESI interfaces for liquid sample introduction
  • Waters Nanoacquity UPLC system

Submitting samples for mass spectrometry analysis by GCMS, LCMS or high resolution MS:

1. 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 the sample submission tray in the instrument room (W303 Discovery).

2. Place a vial, labeled with your sample ID, containing >1 mg (solids) or >10 μl (liquids) in the numbered sample submission rack in the instrument room (W303 Discovery).  Samples are to be submitted in labeled 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.

3. 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 that 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, with the most training required for the LCMS
NMR UVM chem

To make a request for mass spectrometry service, please fill out this PDF request form.