Nuclear Magnetic Resonance
The Virginia Tech NMR Facility operates high-field superconducting magnets ranging from 400-600 MHz for cutting-edge research in chemistry, materials science, and related fields. Our facility provides state-of-the-art instrumentation with comprehensive user training and support.
| per hour | ||||
|---|---|---|---|---|
| Instruments | Internal | Federal | External | Expedited |
| Instrument Time | $9.90 | $15.90 | $125.00 | $187.25 |
| Tech Assist | $40.00 | $64.40 | $125.00 | --- |
Medical Devices & Implants
STOP: If you have any of the following, you MUST get staff clearance before entering:
- Cardiac pacemakers or ICDs
- Cochlear implants
- Neurostimulators (deep brain, spinal cord, vagus nerve)
- Aneurysm clips
- Metallic foreign bodies (shrapnel, metal fragments)
"MRI Safe" ≠ "NMR Safe" — Our magnets operate at much higher fields (9.4-14.1 Tesla) than clinical MRI (1.5-3.0 Tesla)
DANGER: Magnetic Field Hazards
The danger of the magnetic field is proportional to the size of an object:
Projectile Hazard (Heavy Items): Heavy metal objects like large metal carts or heavy tools must NEVER cross the 5 Gauss line marked around each magnet, as they will become dangerous projectiles. Gas cylinders are absolutely prohibited without explicit staff authorization.
Equipment Hazard (Small Items): Items like paper clips or bobby pins are attracted when very close to the magnet. Although they won't become projectiles, small items can get pulled onto the magnet unnoticed and interfere with the shims.
- Submit training request via email facility staff
- Complete general facility training covering:
- Safety protocols and hazards
- Sample preparation essentials
- Instrument operation and queues
- Accessing your data
- Receive shared group credentials for:
- Instrument login
- LOGS data access
- FACES scheduling system
- Door code access (provided with facility training)
Additional training required for:
- Variable Temperature (VT) experiments (-40°C to +135°C)
- Diffusion/DOSY measurements
- Solid-State MAS (4mm Rotor)
- Advanced Water Suppression techniques
- Quantitavtive NMR
- EPR (Electron Paramagnetic Resonance)
Safety Policies
Critical Safety Rules
- Remove mechanical watches before approaching magnet during sample insertion:
- Mechanical watches will be permanently magnetized and ruined
- Piercings and jewelry are generally safe, but take care if large and ferromagnetic
- NMR tube transport: Always use secondary containment (no glass containers)
- Magnet quench: If you hear loud roar/boom or see dense fog, leave immediately and contact NMR staff
- Report all incidents: Spills, breakage, instrument issues, or safety concerns immediately
- Emergencies: For urgent safety issues (quench, injury, fire, significant chemical spills) — especially outside normal business hours or on weekends — contact NMR staff by phone immediately at 540-267-6502. Do not wait for an email reply in an emergency.
- Never work alone if handling potentially hazardous samples
- Know the location of emergency exits and safety equipment
- Keep your phone accessible for emergency communication
- If a magnet quench or safety incident occurs, evacuate immediately and contact NMR staff
Do NOT use chipped, cracked, or damaged NMR tubes.
Damaged tubes can:
- Cause instrument downtime and costly probe damage
- Get stuck in the magnet or autosampler
- Produce poor quality spectra
Tube Retirement Guidelines:
- Chips or cracks: Any visible damage — retire immediately
- Heavy scratches: Deep scratches affect spinning and shimming
- Bent tubes: Even slight bends cause problems
- Multiple uses: Disposable tubes should generally be used 1-3 times maximum
Instrument Type: Bruker Avance IV Neo, 600 MHz
Probe Type: Prodigy TCI cryoprobe
- Highest ¹H sensitivity in the facility
- Reserved for dilute samples and ¹H-detected 2D/3D experiments
Instrument Type: Bruker Avance IV Neo, 500 MHz
Probe Type: Prodigy BBO cryoprobe
- Primary destination for long ¹³C and X-nucleus work
- Roughly 9–12× faster than 400 MHz RT probes
Instrument Type: Bruker Avance IV Neo, 500 MHz
Probe Type: Prodigy BBO cryoprobe
- Reservation-only cryoprobe system
- High sensitivity with flexible VT capability
- Scheduled via FACES
Instrument Type: JEOL ECZL400, 400 MHz
Probe Type: ROYAL HFX
- Facility's primary ¹⁹F instrument
- Lowest ¹⁹F background; only system for ¹H-¹⁹F correlation
Instrument Type: Bruker Avance IV Neo, 400 MHz
Probe Type: 5 mm iProbe
- High-throughput ¹H and ¹³C workhorse
- Strict 20-minute per-sample limit
Instrument Type: Bruker Avance IV Neo, 400 MHz
Probe Type: 5 mm iProbe (RT), 4 mm SSNMR MAS iProbe, 10 mm BBO probe, DiffBBI diffusion probe
- Specialty instrument for polymers, solid-state NMR, diffusion
- Routine 5 mm use only when not in specialty config
Instrument Type: Bruker Avance IV Neo, 400 MHz
Probe Type: DiffBB diffusion probe, additional high-gradient diffusion probes
- Dedicated diffusion NMR instrument
- Managed by Madsen Research Group; not for general walkup
Best choice: Neo400HT or JEOL ECZL400
For fast, routine proton spectra on concentrated samples. Neo400HT has a strict 20-minute limit per sample; JEOL allows up to 60 minutes. Both are walkup instruments with no reservation needed — ideal for reaction monitoring or quick structure checks.
Best choice: Neo500BBO or Neo500Oxford
These Prodigy BBO cryoprobe systems deliver roughly 9–12× the sensitivity of a 400 MHz room-temperature probe, cutting multi-hour ¹³C or X-nucleus experiments down dramatically. Neo500BBO is walkup/queued; Neo500Oxford requires a FACES reservation.
Best choice: Neo600TCI
The highest ¹H sensitivity in the facility, thanks to its proton-optimized TCI cryoprobe. Best reserved for dilute samples or inverse-detected 2D/3D experiments where proton sensitivity is the limiting factor — not for routine ¹H screening or ¹³C work.
Best choice: JEOL ECZL400
Lowest ¹⁹F background and best ¹H–¹⁹F correlation on-site. Its ROYAL HFX probe offers two-channel decoupling, allowing simultaneous ¹H/¹⁹F decoupling during ¹³C acquisition, or ¹H-decoupled ¹⁹F — simplifying spectra of complex fluorinated compounds that would otherwise show overlapping multi-nucleus couplings
Best choice: JEOL ECZL400 or Neo500Oxford
Variable-temperature work requires dedicated VT training and staff approval. These are currently the only two instruments configured for user-adjustable VT in this range; more extreme temperatures remain staff-only.
Best choice: Neo400Jack (10mm) or Neo500BBO
The 10 mm probe's larger bore handles viscous, sticky, or partially soluble polymer samples that are hard to work with in a standard 5 mm tube. Requires a staff-scheduled probe swap and specialized training for independent use.
Best choice: Neo400Jack DiffBB or Neo400Diff
For diffusion-ordered spectroscopy on mixtures, polymers, or electrolytes. Requires diffusion-specific training covering gradients, timing, and convection artifacts; sessions are staff-scheduled. Neo400Diff is managed separately by the Madsen group.
Best choice: Neo400Jack (4mm MAS)
For magic-angle spinning experiments on powders, crystalline materials, or solid polymers. Rotor packing and spin-rate handling are done by staff due to hardware risk; independent use requires MAS-specific training and a sustained project need.
Two acquisition parameters primarily control 2D experiment quality and time: Number of Scans (NS) and Number of Increments (NI).
NS (scans per increment) sets the signal averaging at each point in the indirect dimension. Because most 2D sequences (HSQC, HMBC, COSY) use sensitivity-enhanced detection and efficient phase cycling, useful spectra often need far fewer scans than a comparable 1D experiment. The right NS depends primarily on your sample's concentration:
- 1–2 scans: Well-concentrated samples (routine 10–80 mM small molecules) — signal is already strong.
- 4–8 scans: Moderately dilute samples where a bit of extra averaging improves clarity.
- 16–32 scans: Dilute or limited-quantity samples needing meaningfully more signal averaging.
- 64, 96, or even 128 scans: Extremely dilute samples, most common in natural products characterization where material is scarce and concentration is low.
Increasing NS raises signal-to-noise only with the square root of scans, so doubling NS gives just a ~40% SNR gain — a costly trade for marginal improvement. At the high end of this range, combined with high increment counts (NI), a single 2D experiment can take well over a full day, so these settings should be used deliberately and coordinated with staff rather than as a default.
NI (increments in the indirect dimension) sets the resolution along the F1 axis. Total experiment time scales with NS × NI, so doubling NI roughly doubles run time for a fixed NS. The right NI depends on how much you need to resolve overlapping signals in the indirect dimension:
- 128 or 256: Coarse resolution for quick structural checks or routine assignments — sufficient when peaks are reasonably well separated.
- 400 or 512: Higher resolution for crowded or overlapping spectra where signals need to be cleanly separated in F1.
A coarser NI is often perfectly adequate for routine work, since it's the total experiment time — not the appearance of resolution — that scales directly with this choice. Combined with high NS on a dilute sample, a high-NI 2D experiment (HMBC especially) can easily run well over a full day, so increasing NI should be a deliberate decision based on demonstrated need (visibly overlapping cross-peaks at lower NI), not a default starting point.
COSY — Shows ³J ¹H-¹H scalar couplings (2–3 bonds). Used to identify spin systems and proton connectivity. Typical time: 10–30 min.
TOCSY — Shows extended ¹H-¹H relayed couplings through spin systems. Used to map entire spin systems (e.g., sugar residues). Typical time: 30–60 min.
HSQC — Shows ¹J ¹H-¹³C direct bonds (CH, CH₂, CH₃). Used to assign protonated carbons; the first heteronuclear 2D experiment run. Typical time: 20–60 min.
HMBC — Shows ²J–⁴J ¹H-¹³C long-range couplings. Used to connect to quaternary carbons and resolve branching. Typical time: 1–4 hrs.
H2BC — Shows ²J ¹H-¹³C geminal couplings only. Used for clean methylene (CH₂) assignments and to confirm HMBC data. Typical time: 1–3 hrs.
NOESY — Shows through-space ¹H-¹H dipolar interactions (<5 Å). Used to determine stereochemistry and 3D conformation (MW >800 Da). Typical time: 1–3 hrs.
ROESY — Shows rotating-frame NOE (positive for all molecular weights). Used for mid-sized molecules (500–1500 Da) where NOESY fails. Typical time: 1–3 hrs.
Internal PO Submission Process
How to fill out an Analytical Services ISR
Supplier: "VT Chemistry NMR Lab"
External Measurement Request
Contact Ken Sharp-Knott
kknott@vt.edu
540-231-0885
Walkup Instruments (No Reservation Needed)
- Neo400HT: 20 minute hard limit per sample
- JEOL ECZL400: 60 minute daytime limit per sample
- Neo400Jack: Prioritized for scheduled use of specialty probes
- Neo500BBO & Neo600TCI: No formal limit, but experiments exceeding 2 hours should be moved to the night queue when possible
Reservation Only Instrument
- Neo500Oxford: Direct link to FACES Scheduling System
- FACES Group: VATECHNMR
- Can reserve up to the minute — No shows risk loss of privleges
In all cases, when possible run non-urgent experiments longer than 2 hours during the overnight queue to maintain fair access for all users.
All data automatically uploaded to LOGS server:
URL: https://nmrsc.chem.vt.edu/asds
Login: Same credentials as FACES and instrument login
- Download datasets from LOGS to your local computer
- Process in MNova (facility standard software)
- Save MNova file (each file should contain experiments for ONE compound)
- Site license provided by facility upon completion of training
- Must connect to VT networkfor validation
- On-campus: edurom
- Off-campus: Cisco AnyConnect VPN
User Data Storage Recommendations: Download and archive your data promptly and systematically.
- Back up both the raw LOGS zip and the processed .mnova file for every sample, stored together in one folder.
- Never leave data in a Downloads folder — move it to permanent group storage the same day.
Technical reference materials for planning experiments, selecting parameters, and understanding NMR fundamentals.
Sample Preparation Essentials
| REQUIRMENT | SPECIFICATION |
|---|---|
| Tube | Straight, undamaged 5mm tube (high-quality for qNMR and VT) |
| Volume | ~0.6 mL (40-50mm liquid height in tube) |
| Solution | Fully dissolved, clear, no particulates or bubbles |
| Solvent | Deuterated (CDCl₃, DMSO-d₆, D₂O, CD₃OD, CD₃CN, acetone-d₆, toluene-d₈, benzene-d₆) |
| Cleanliness | Wipe tube exterior with lint-free tissue before insertion |
- FORMAT: GROUPID-USERINITIALS-SHORTSAMPLEID
- EXAMPLE: WS2-KK-SK21
- RULES: Alphanumeric characters only - no spaces, periods, or special characters
- REQUIRED: Write GROUP ID prominently around cap (required for sample identification)
- Use BLACK SHARPIE (fine-tipped) on light colored cap
- Include sample ID or your initials (strongly recommended to distinguish your samples from groupmates)
- Dark or illegible caps not allowed — slows troubleshooting and makes orphaned samples harder to track
- No tape, parafilm, or labels attached to tubes — write directly on cap only
- Damaged or poor-quality tubes: Chips, bends, or scratches degrade shimming and cause spinning issues or distorted peaks. Retire questionable tubes, especially for VT or quantitative work.
- Incorrect sample volume or height: A liquid column far from 40–50 mm underfills or overfills the coil, hurting sensitivity and resolution. Target ~0.6 mL.
- Incomplete dissolution, particulates, or bubbles: Undissolved material or bubbles cause broad, unstable lines. Filter or let settle before running.
- Incorrect sample depth in spinner: Always set depth with the gauge — wrong depth causes weak signal and hard-to-shim spectra.
- Poor shimming: Shows up as broad or asymmetric peaks— more scans won't fix it. Before blaming shimming, first rule out the four causes above.
Quick Reference Guides
Cost consideration: Deuterated solvents vary significantly in price. CDCl₃ and DMSO-d₆ are relatively inexpensive, while D₂O, CD₃OD, and specialty solvents (DMF-d₇, pyridine-d₅) are more costly. Plan accordingly for budget-sensitive projects.
DMSO-d₆ (Dimethyl sulfoxide-d₆)
- Residual ¹H peak: 2.50 ppm
- Boiling point: 189°C
- Freezing point: 19°C
- Notes: Hygroscopic, best solvent for observing exchangeable OH/NH protons. High boiling point makes sample recovery difficult; can solidify in a cool lab.
D₂O (Deuterium oxide)
- Residual ¹H peak: 4.79 ppm
- Boiling point: 101°C
- Freezing point: 4°C
- Notes: For aqueous samples, salts, and biomolecules. Exchanges rapidly with labile OH/NH/SH protons, so those signals disappear. No usable ¹³C reference — requires an external standard (DSS or TSP).
CD₃OD (Methanol-d₄)
- Residual ¹H peak: 3.31 ppm (CHD₂), 4.87 ppm (OH)
- Boiling point: 65°C
- Freezing point: -98°C
- Notes: Protic. Like D₂O, causes fast exchange of labile protons. Can slowly deuterate acidic C–H sites next to carbonyls and risks methanolysis of esters or acyl chlorides.
CD₃CN (Acetonitrile-d₃)
- Residual ¹H peak: 1.94 ppm
- Boiling point: 82°C
- Freezing point: -45°C
- Notes: Aprotic with a wide liquid range. Low viscosity gives sharp lines. Water peak sits very close to the residual solvent peak (2.1 ppm) — check both before interpreting that region.
Acetone-d₆
- Residual ¹H peak: 2.05 ppm
- Boiling point: 56°C
- Freezing point: -95°C
- Notes: Volatile — easy solvent recovery. Highly hygroscopic; reacts with primary/secondary amines, so avoid for amine-containing compounds.
CDCl₃ (Chloroform-d)
- Residual ¹H peak: 7.26 ppm
- Boiling point: 61°C
- Freezing point: -64°C
- Notes: Most common solvent, good for nonpolar to moderately polar organics. Watch for slow decomposition to HCl/phosgene with age or light exposure; use freshly opened or stabilized bottles for sensitive samples.
Toluene-d₈
- Residual ¹H peak: 2.09 ppm (CD₂H), 7.00–7.20 ppm (aromatic)
- Boiling point: 111°C
- Freezing point: -95°C
- Notes: Aromatic, useful for high-temperature VT work with polymers. Aromatic multiplet can overlap with sample aryl signals.
Benzene-d₆
- Residual ¹H peak: 7.16 ppm
- Boiling point: 80°C
- Freezing point: 6°C
- Notes: Aromatic, used for organometallic and materials chemistry. Known human carcinogen — fume hood use only.
NMR Tubes & Consumables
- Quantitative NMR (qNMR): Use high-quality, precision tubes (e.g., Wilmad 528-PP)
- Variable Temperature (VT): VT-rated tubes (Class A) required for temperature extremes
- Cryoprobe work: Clean, undamaged tubes to protect expensive cryoprobes
| Tube Type | When to Use | Notes |
|---|---|---|
| Shigemi tubes | Limited sample volume (<300 μL) | Glass susceptibility-matched plugs; consult staff before use |
| Coaxial inserts | Lock solvent separate from sample | For samples incompatible with deuterated solvents |
| 3 mm tubes | Very limited sample quantity | Requires 3mm probe (not standard); discuss with staff |
When co-authorship is expected:
- Substantial intellectual contributions to experimental design, data interpretation, or manuscript preparation
- Specialized technique development or troubleshooting beyond routine support
- Custom method development, extensive troubleshooting, or data analysis assistance
When acknowledgment (not co-authorship) is sufficient:
- Routine training and instrument access
- Standard walkup experiments without significant staff involvement
- Minor troubleshooting or parameter adjustments
Best practice: Discuss authorship expectations early in your project with facility staff to avoid misunderstandings.
When describing your NMR experiments in the Methods or Experimental section of manuscripts, cite relevant instrument details from the Instruments page. Include:
- Instrument name (e.g., "Bruker Avance IV Neo 600 MHz")
- Probe type (e.g., "Prodigy TCI cryoprobe")
- Field strength and observe frequency
Example Citation:
"¹H and ¹³C NMR spectra were acquired on a Bruker Avance IV Neo 600 MHz spectrometer equipped with a Prodigy TCI cryoprobe. NMR data reported in this work were obtained at the Virginia Tech Chemistry NMR Facility (RRID:SCR_027587)."
- Specify solvent, temperature (if non-ambient), and spectrometer frequency
- Include coupling constants (J) in Hz for multiplets
- For quantitative NMR, describe relaxation delays, pulse angles, and any relaxation agents used
Laboratory Hours
Staffed Hours: 9a - 5p, M-F
24/7 access for trained users
Contact NMR Staff
Ken Sharp-Knott
NMR Facility Manager
kknott@vt.edu
540-231-0885
540-267-6502 (Emergencies Only)
Murthy Shanaiah, Ph.D.
NMR Spectroscopist
nmrns@vt.edu
540-231-8256
Emergency Contact
VT Environmental Health & Safety
540-231-5364
www.ehs.vt.edu
Kenny Smith
Facilities Manager
kesmith7@vt.edu
Drew Murphy
Safety Coordinator
drewmurphy23@vt.edu
Lab Address
Hahn Hall South 002
Virginia Tech
800 W. Campus Blvd.
Blacksburg, VA 24061