Liquid-State NMR and Scalar Couplings in Microtesla Magnetic Fields

• DOI: 10.1126/science.1069280
• Publication Date: 2002-07-27T09:35:18Z
• Authors: Robert McDermott; Andreas H. Trabes...; Michael Mück; Erwin L. Hahn; Alexander Pines; John Clarke
• Keywords: Chemical shift

We obtained nuclear magnetic resonance (NMR) spectra of liquids in fields a few microtesla, using prepolarization millitesla and detection with dc superconducting quantum interference device (SQUID). Because the sensitivity SQUID is frequency independent, we enhanced both signal-to-noise ratio spectral resolution by detecting NMR signal extremely low fields, where lines become very narrow even for grossly inhomogeneous measurement fields. In absence chemical shifts, proton-phosphorous scalar (J) couplings have been detected, indicating presence specific covalent bonds. This observation opens possibility “pure J spectroscopy” as diagnostic tool molecules