A downloadable pdf of this manual can be found here.
The use of the NMR instrumentation within the Department of Chemistry is a privilege for users, not a right. It is of utmost importance that each user understands all of the safety hazards and complies with correct standard operating procedures. Failure to do so can result in instrument damage and more seriously, personal injury and even death. Due to the high cost of the NMR equipment and related repairs all users must inform the NMR personnel of all issues with the equipment and not attempt any repairs themselves. Failure to do so will result in the suspension of privileges. The NMR staff can be found in room WB-13 (phone: 22573).
To obtain the NMR phenomenon large magnetic fields are needed. Magnetic field strengths of 7.0 Tesla to 16.5 Tesla (compare with the Earth's magnetic field of ~1x10-4 T; 1 Tesla = 10000 Gauss) can be found within the Department of Chemistry. There are large attractive forces associated with these magnets and in fact, every magnet has a stray magnetic field that extends out past the physical structure of the magnet. These attractive forces will be exerted on equipment and people brought into proximity of the magnet. The closer to the magnet one goes the larger the attractive force. The larger the mass of the equipment, the larger the attractive force. The safety zone or 5 G (5 x10-4 T) line is indicated by signs, plastic chains, and/or marks on the floor around each NMR magnet.
Inside the 5 G line, near the magnet:
The spectrometer host computer is situated outside the 5 G line. It is recommended to the end user to remove all metallic objects and valuables (i.e. coins, cell phones, bank cards, watches, etc.) from their person and leave them beside the spectrometer host computer before approaching the magnet.
Persons with medical implants and devices are recommended to stay outside of the labs that house the NMR spectrometers. Warning signs are posted at the entrance of all NMR labs, shown below.
Gas cylinders and other equipment should be brought into and around the NMR magnets only by the authorized personnel (i.e. the NMR staff).
2. Magnet Quench
Superconducting NMR magnets contain a large solenoid or coil made up of several kilometers of superconducting wire. This coil resides in a bath of liquid helium (up to 260 L for some NMR magnets within the Department). The wire contains and passes electric current without resistance only when cryogenically cooled to 4 K by liquid helium; the current contained in the coil produces the magnetic field. Should the solenoid or cryogenic system fail, the wire becomes resistive and generates heat as the electric current stored in the solenoid is lost; a situation referred to as a magnet quench. During a magnet quench, there will be a sudden, large, rapid, and noisy expulsion of helium gas from the magnet (Fig. 3) as liquid helium vaporizes into a gas (1L of helium turns in to ~800L of gas). Magnet quenches are very rare events but if a quench occurs:
What to do in case of a quench:
Due to the number of NMR magnets and/or room size, rooms W1-19, SB-3E, and EB-44 have oxygen sensors with audible and visual alarms, shown below, Fig. 4. These alarms will sound (potentially due to a magnet quench) when oxygen levels have been reduced to unsafe levels. If these alarms sound DO leave the room immediately and/or DO NOT enter the room.
3. NMR tubes and samples
NMR tubes are thin-walled glass tubes and are fragile. Although they are used daily personal injury can (and has) resulted when fixing the cap to the tube and inserting the tube into the spinner or turbine.
When handling your NMR tube we recommend:
Broken samples are inevitable however care must be taken by the end user to ensure the health and safety of the other users of the NMR facility. Many samples are unknown entities that can be harmful. The items at the spectrometer host computer are communal items that everyone uses, the depth gauge, spinner, mouse, keyboard and desk. Some of these items do need to be disassembled to be cleaned properly. If a sample breaks, the end user is required to:
NMR magnets tend to be quite large. Steps and/or ladders are provided to facilitate putting your sample in the magnet. Take caution to avoid losing your balance and falling.
Due to the multiuser environment and high throughput of the NMR facility within the Department of Chemistry it is not recommended to eat in the lab. Beverages are permitted.