The NMR facility manages four superconducting pulsed Fourier-transform NMR instruments with proton frequencies of 600, 500, 500, and 400 MHz. We have a campus-wide site license for the MestReNova NMR data processing software.
- Bruker DRX-600 with triple-resonance, shaped pulse and 3-axis gradient capabilities (installed August, 1999)
- Bruker NEO-500 with dual-resonance, multiple receiver and SampleJet automation (installed August 2020)
- Bruker DRX-500 with triple-resonance, shaped pulse and 3-axis gradient capabilities (installed January, 1999)
- Bruker AVIII-400 (installed in 2009) with SampleJet automation
1) Bruker DRX-600 Purchased used (3 years old) in 1999 and installed in August of 1999, the Bruker DRX-600 has triple-resonance and triple-axis gradient capabilities. It has been upgraded to include a fourth channel and 2H transmitter for 2H decoupling, as well as updated software to allow for 3-axis deuterium gradient shimming and easy setup of biological 3D experiments. This instrument is currently used for small biological molecules such as glycopeptides, particularly in association with micelles. It is also used for 2D experiments on complex natural products, and the 3 mm 13C probe permits 13C and DEPT on submilligram organic samples, as well as INADEQUATE on biosynthetically labelled samples.
The actively-shielded 14.1 Tesla Magnex magnet is equipped with vibration-damping legs (grey). The stability and resolution of this magnet are "sweet". Users have a choice of three probes: A Bruker TXI 5 mm triple-resonance (HCN) 3-axis gradient probe, a newer Nalorac 5 mm triple-resonance Z-axis gradient probe and a Nalorac 3 mm direct CH probe with Z-axis gradient. Temperature control of the sample (7oC - 60oC) is provided by a Whatman air dryer, Bruker BCU 05 air chiller and a BVT 3000 controller.
The Avance DRX console has a 3-axis gradient controller and amplifier, four full RF channels (each equipped with shaped pulse capability), and high power pulse amplifiers for H, X and Y with a 20 W 2H amplifier. The gradient pre-emphasis unit allows users to balance the gradient amplifiers more conveniently.
2) Bruker NEO-500 The NEO 500 was installed in August of 2020 and is fully equipped for automated high-field NMR: Two RF channels with multiple receivers, pulsed field gradients and SampleJet. This instrument was purchased with funds from NSF. The instrument is housed in Old Chemistry and operated by the Chemistry Department NMR Facility. Time is available to all researchers on campus and external users.
3) Bruker DRX-500 The Oxford 11.7 Tesla unshielded magnet began its life as part of a Bruker AM-500 spectrometer. In January of 1999 the console, computer, upper bore tube, room temperature shims and probes were replaced to give the instrument triple-resonance, 3-axis gradient capability. The $330,000 for the upgrade came from an NSF Biological Multi-User Equipment grant, including a 50% match from the University. The DRX-500 has become the workhorse instrument for routine 1H and 13C spectra of organic samples, but is also used for selective 1D experiments (NOE, TOCSY) and 2D experiments (COSY, HSQC, HMBC, TOCSY, ROESY, NOESY). In 2009 the computer was replaced with a Linux workstation running Topspin 1.3 software, and a 2H transmitter board was added to allow automated 2H gradient shimming. A new probe (5 mm Bruker BBO Z-gradient) was added for direct-detect broadband (15N to 31P) applications.
The unshielded Oxford 11.7 Tesla magnet is equipped with inflated-tire vibration dampers. In addition to the new BBO probe, we have two 3-axis gradient probes: Nalorac 5 mm inverse HCN and Nalorac 5 mm inverse broadband HX probe. Temperature control of the sample (7oC - 60oC) is provided by a Whatman air dryer, Bruker BCU 05 air chiller and a BVT 2000 controller. The magnet drifts down and requires lowering the 1H frequency by 100 kHz every 18 months.
The Avance DRX console has a 3-axis gradient controller and amplifier, a third (X nucleus) channel pulse amplifier and three full RF channels, each equipped with shaped pulse capability. The Digital Quadrature Detection (DQD) capability eliminates F2 artifacts in fast 2D experiments on concentrated samples.
4) Bruker AVIII-400 The Bruker AVIII-400 was installed in November, 2009. It is equipped with a BBOF (Broadband 5mm Direct Z-Gradient) Probe and a BBI (Broadband 5mm Inverse Z-Gradient) Probe. The BBOF probe is tuneable to 19F on the broadband coil. The SampleJet autosampler is a revolutionary new concept: The NMR sample is picked up by its cap and inserted into a "shuttle" which grips the sample at the top of the bore and carries it into the magnet. Only a single shuttle is used, with capacity for 480 course samples (in 4 inch tubes in 5 racks of 96 tubes each) and an additional 96 research samples (in 7 inch tubes, hung on slots around the edge of the carrousel). Operation of the instrument is fully automated, using ICON-NMR software and automatic lock, tune/match and 2H gradient shimming. Fast experiments go into the day queue and longer experiments are deferred to nights and weekends. Data are deposited as zip files on a website, where they can be picked up by the users and processed using MestReNova software. We have a permanent campus-wide license for this user-friendly package running on Windows, Linux and Mac platforms.
The AVIII-400 also has a solid-state capability, with basic CP-MAS and top-loading rotors. Solid-state experiments will be run at night or on weekends and should not interfere with the automation queue. The magnet is ultrashielded with a 1 meter radius 5 G limit. The instrument is installed in a large room with space for an "NMR classroom". This will include seating for 24 students, projector and screen, and webcam to show the operation of the autosampler.AVIII-400 NMR:
Bruker Ultrashield 9.4 Tesla magnet with TMC anti-vibration legs (background), SampleJet autosampler (top), microbay console (right) and Linux workstation (left), shown with (left to right) Dr. Guangxin Lin, Bryan Korth and Dr. Neil Jacobsen.