Triple axis gradients

All NMR experiments were performed on a Bruker DRX700 spectrometer operating at 700 MHz H frequency and equipped with a triple resonance probe and a triple axis gradient coil. DHPR concentration was 75 pM (300 mM monomer) in 25 pM d1rTris buffer, pH = 7.8 and 7=303 K. (Taken from Ref. [4]). 

Gradients are used in conjunction with frequency-selective soft (also referred to as narrowband) RF pulses. These types of experiments in the physical sciences are usually referred to as MR microimaging [78] and can be conducted on a standard wide or narrow bore NMR spectrometer using specialised probes and triple-axis gradients. A resolution of tens of microns (similar to optical microscopy) is achievable with MR microimaging. A more comprehensive explanation of the MRI techniques in the physical sciences can be found in one of the excellent referenced texts [77, 79]. 

About 150 mg of each sample (1 , 2" and 3 generation wedges(41 was dissolved in 0.7mL deuterated acetone in a 5 mm NMR tube for NMR studies. NMR spectra were obtained on a Varian Vnityplus 750 MHz NMR spectrometer equipped with four RF chatmels, a Performa II z axis pulse field gradient (PPG) accessory, and a Varian H/ C/ P/ H foin chapel triple resonance probe with a PFG coil. Acetone-de was also used as internal references for both H (2.05 ppm) and C (29.92 ppm) chemical shifts. All experiments were performed at 25.0 0.1 °C. All data were processed with Varian s VNMR software on a SUN Ultra-10 workstation. 

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