Indiana State University : Department of Chemistry : NMR Facilities

Bruker AC-250 NMR spectrometer

Until recently, our primary research instrument was a Bruker AC-250 high-field NMR spectrometer which was purchased in 1993 under an Instruction and Laboratory Improvement (ILI, now CCLI) program from the National Science Foundation.

The Bruker AC-250 is a superconducting NMR spectrometer. The field of the magnet is 5.9 Tesla and operates at a nominal proton frequency of 250 MHz. The magnet is a Bruker Ultra-Long Hold magnet with a nominal helium fill interval of 6 months and was one of the first of its kind available for NMR spectroscopy. It is a two-channel instrument and is equipped with a 5mm broadband probe covering the range from ¹⁵N to ³¹P with proton observation. We also have a magic angle spinning (CPMAS) accessory (left) and probe. Each of the probes supports variable temperature operation controlled through the console.

Also present is an PC linked via ethernet cable for offline processing. We have three licenses for the Bruker WINNMR software for processing 1D data. 2D spectra are processed and printed from the console to an attached laser printer. The AC-250 was housed in room S34A.

AC-250 Operation (abbreviated for undergraduate students in Chemistry 355)

A fond farewell to the AC-250
The AC-250 was de-energized and vented on January 3, and renovation has begun on the NMR room. We have decommissioned the magnet and will be cutting it open as a display piece.