Poster Presentation Australian & New Zealand Society of Magnetic Resonance Conference 2017

Suppression of Multiple Sites Using Binomial Type Pulses (#121)

Scott A. Willis 1 , Gang Zheng 1 , Allan M. Torres 1 , Tim Stait-Gardner 1 , William S. Price 1
  1. Nanoscale Organisation and Dynamics Group, Western Sydney University, Locked Bag 1797, Penrith, NSW, Australia

Suppression of unwanted signals in NMR is a powerful tool for the experimentalist. There are several approaches to suppression of one signal (e.g., water) available.[1] However, there are numerous situations that demand good suppression of multiple signals (e.g., LC-NMR[2] and component analysis/profiling of alcoholic beverages[3]). Various multiple solvent suppression sequences exist, e.g., multi-site WET,[2a] MULTIGATE,[4] suppression via NOESY (with pre-saturation)[3a, 3d, 5] or forms of WATERGATE[6] modified to have multisite suppression using either concatenated singly selective rf pulses interleaved with hard π rf pulses between each gradient pair[7] or concatenated/successive double echoes each with singly selective rf pulses acting on different frequencies.[8] Such sequences have preferably utilised singly or multiply selective shaped rf pulses. However, shaped pulses are inherently complex, can become long if they are made selective for multiple frequencies and the sequences may require additional pre-saturation and trim pulses. This can increase the pulse sequence length thereby limiting their application, for example, to LC-NMR.[2a] The multiply selective WET sequence has proven useful for LC-NMR under flow conditions[2a] but still requires complex shaped rf pulses. Here we report on a multiple suppression sequence using binomial type pulses that is easily implemented and modular enabling simple extension to any number of peaks/regions. Further, even when suppressing a number of resonances the sequence is relatively short thereby facilitating applications.

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