title: Quadrupole sensitive pulse for signal filtering.
abstract: A longstanding problem in quadrupolar NMR of semi-solids is the selection of signals originating from ordered nuclei, i.e. those that experience a non-vanishing quadrupolar coupling. Established techniques, such as for example multiple-quantum filters are not adequate in situations when the radio frequency power is on the order of the quadrupolar coupling or the quadrupolar relaxation rates, such as may be the case on an MRI scanner, or in ex situ applications. In this manuscript we show a new method for the selective excitation of ordered spin-3/2 nuclei, which produces the desired results when the radio frequency power is approximately equal or smaller than quadrupolar frequency. Using a combination of simulations and experiments with (23)Na in NaCl solution, Pf1-solutions, and bovine patellar cartilage samples we further show how the value of the quadrupolar frequency and global features of a quadrupolar coupling distribution can be extracted from these experiments.
authors.affiliation: Department of Chemistry, New York University, New York, NY 10003, USA.
authors.forename: Nimerovsky
authors.initials: N
authors.lastname: Evgeny
authors.affiliation: Department of Chemistry, New York University, New York, NY 10003, USA. Electronic address: alexej.jerschow@nyu.edu.
authors.forename: Alexej
authors.initials: A
authors.lastname: Jerschow
mesh_terms: D000465:Algorithms; D000818:Animals; D025561:Bacteriophage Pf1 / Q000737:chemistry; D002358:Cartilage, Articular / Q000737:chemistry; D002417:Cattle; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010329:Patella / Q000737:chemistry; D011846:Radio Waves; D012965:Sodium Chloride / Q000737:chemistry; D012975:Sodium Isotopes
chemical_list: D012975:Sodium Isotopes; D012965:Sodium Chloride
keywords: Na NMR; Quadrupolar coupling; Quadrupole selective pulse; Tissue; Weak radio frequency fields