4521732 Pulse sequence for use in performing nuclear magnetic resonance spectroscopy

Abstract

A liquid sample comprising a system made up of two types of heteronuclei is pulsed in a particular manner in a nuclear magnetic resonance (NMR) experiment so that the resulting NMR signal from the one type of heteronucieus depends on the scalar-coupled interaction with the other type of heteronucleus. The sequence of radiofrequency pulses is such that the two types of heteronuclei interact via the phenomenon of polarization transfer and by the phenomenon of the correlated motion of the two types of heteronuclei in the transverse plane of the doubly rotating reference frame. The combination of these two phenomena in the one pulse sequence provides NMR signals which are easily made less dependent on the exact magnitude of the heteronuclear scalar coupling constant. The coupled NMR signals for polarization transfer from a system of multiple spin-half nuclei have multiplet components in the normal ratio. Consequently the pulse sequence provides an improved method for obtaining chemical structural information. Applications include the provision of accurate edited subspectra; polarization transfer between any number of one type of heteronucleus of any spin number and any number of a second type of heteronucieus of any spin number; and two-dimensional NMR spectroscopy.