Nuclear magnetic resonance transverse relaxation measurement method without J-coupling-effect interference

Abstract

A nuclear magnetic resonance transverse relaxation measurement method without J-coupling-effect interference is suitable for a routine liquid magnetic resonance spectrometer. The nuclear magnetic resonance transverse relaxation measurement method without J-coupling-effect interference can eliminate the J-coupling-effect interference. The method comprises the steps of (1), measuring a pi / 2 nonselective RF pulse width required for exciting a sample; (2), introducing a nuclear magnetic resonance pulse sequence into the magnetic resonance spectrometer; (3), starting a transverse relaxation evolution module and a pure chemical shift decoupling module based on a perfect echo for the nuclear magnetic resonance pulse sequence, and setting experiment parameters of the transverse relaxation evolution module and the pure chemical shift decoupling module; (4), performing three-dimensional data sampling; and (5), after data sampling, performing related data after-processing operation, and obtaining a two-dimensional spectrum of which the direct dimension is the pure chemical shift information and the indirect dimension is the transverse relaxation time and error, namely a pure chemical shift-transverse relaxation time two-dimensional correlation spectrum.

Description

technical field [0001] The invention relates to a spectroscopy method for nuclear magnetic resonance (NMR, Nuclear Magnetic Resonance) kinetic information detection, in particular to a NMR transverse relaxation measurement method without J-coupling effect interference which can eliminate J-coupling effect interference. Background technique [0002] NMR (Nuclear Magnetic Resonance, NMR) spectroscopy, as a non-invasive non-destructive testing analysis technology, is widely used in chemistry, biology, materials and other disciplines, especially hydrogen NMR spectroscopy is the most widely used. NMR spectroscopy can not only provide structural information such as molecular structure and spin-nuclear coupling network, but also provide molecular dynamics information, such as diffusion and relaxation information. Among them, transverse relaxation is an important physical process of nuclear magnetic resonance. Through the detection of transverse relaxation, the dynamic change proces...

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Problems solved by technology

Although the CPMG sequence provides a widely used method for measuring the transverse relaxation time, the method also has some shortcomings

First of all, due to the influence of the J-coupling effect, the peak intensity of the obtained one-dimensional detection hydrogen spectrum will be subject to J-couple modulation, which is prone to amplitude distortion and phase distortion of the spectrum peak signal, and inaccurate measurement of transverse relaxation

Secondly, due to the peak splitting caused by the J-coupling effect and the narrow chemical shift range of the hydrogen spectrum itself, the peak crowding phenomenon often occurs in the one-dimensional hydrogen spectrum, especially for the detection of complex samples.

This phenomenon will lead to inaccurate assignment of the spectral peak signal required for transverse relaxation data fitting

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