A method for suppressing false peaks of nuclear magnetic resonance spectrum sampling truncation

A technology of nuclear magnetic resonance spectrum and sampling data, which is applied in the direction of analysis by nuclear magnetic resonance, material analysis through resonance, and measurement devices. The number of indirect dimension sampling points and the effect of reducing the number of indirect dimension sampling points

Active Publication Date: 2017-09-15
INNOVATION ACAD FOR PRECISION MEASUREMENT SCI & TECH CAS
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  • Application Information

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Problems solved by technology

(A) The spectrogram obtained by complete sampling; (B) The spectrogram obtained by FFT for the sampling truncated signal, in which the false peak caused by sampling truncation is obvious, and the weak signal next to the strong signal peak on the left is covered by the false peak; ( C), using the conventional window function method, the truncated false peaks can be eliminated, but the spectral peaks become wider, and the signals that are close to each other will overlap

Method used

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  • A method for suppressing false peaks of nuclear magnetic resonance spectrum sampling truncation
  • A method for suppressing false peaks of nuclear magnetic resonance spectrum sampling truncation
  • A method for suppressing false peaks of nuclear magnetic resonance spectrum sampling truncation

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Embodiment 1

[0052] Step 1. Set the first percentage threshold p and the second percentage threshold q, the value range of the first percentage threshold p is 95% to 98%, and the value range of the second percentage threshold q 0.005% to 0.015%.

[0053] Step 2, performing zero-filling and Fourier transform processing on the obtained time-domain signal a. The time domain signal a is a length N 1 complex array of The serial number of each element in the complex number array is M, and each element in the complex number array is the signal strength when the sampling time is M·Δt. The zero-filling process for the time-domain signal a is to sequentially add digital zeros at the end of the complex number array, and change the length of the complex number array by N 1 increase to N 2 .

[0054]

[0055] The Fourier transform is to fill the zero-filled time-domain signal a through the following formula The NMR spectrum A is obtained by transforming from the time domain to the frequency ...

Embodiment 2

[0087] Pure Shift experiment is a kind of direct dimension decoupling experiment. In the spectrum obtained by Pure Shift experiment, the coupling splitting is suppressed, and only the chemical shift (Chemical Shift) information is retained, which significantly reduces spectral peak overlap and simplifies spectral analysis. , so it is called the Pure Shift experiment.

[0088] The one-dimensional Pure Shift experiment is actually a pseudo-two-dimensional experiment, which is to extract the first few sampling points from a series of one-dimensional experimental sampling data, splicing them into a new time-domain signal, and then process the signal to obtain final spectrum.

[0089] Therefore, the one-dimensional Pure Shift experiment is more time-consuming than the conventional one-dimensional experiment, but if the number of indirect dimension sampling is reduced, the experimental time can be reduced, but the spliced ​​time-domain signal faces the truncation effect introduced by ...

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Abstract

The invention discloses a suppression method for nuclear magnetic resonance spectrum sampling and truncating false peaks, setting a first percentage threshold and a second percentage threshold; performing zero-filling processing on a time-domain signal a and performing Fourier transform to obtain an NMR spectrum Figure A; divide NMR spectrum A into NMR spectrum B and NMR spectrum C according to the first comparison threshold; judge whether to enter the loop iteration according to the NMR spectrum B and the second comparison threshold to obtain the NMR spectrum B in each loop iteration and NMR spectrum C; the NMR spectrum B obtained in each cycle iteration and the NMR spectrum C obtained in the last cycle iteration are superimposed to obtain the NMR spectrum D; the NMR spectrum D is corrected by window smoothing to obtain the final NMR Spectrum E. The invention can reduce the number of indirect dimension sampling points, improve the experiment speed, avoid sampling truncation false peaks caused by insufficient sampling points, avoid spectral peak broadening and overlapping caused by conventional window function processing methods, and improve spectral resolution.

Description

technical field [0001] The invention relates to the field of nuclear magnetic resonance analysis, in particular to a method for suppressing false peaks of nuclear magnetic resonance spectrum sampling and truncation, which is used for nuclear magnetic resonance analysis of chemical structures. Background technique [0002] 1. Introduction to NMR technology [0003] Nuclei with non-zero nuclear spin quantum numbers will generate magnetic moments in the magnetic field. When the angle between the direction of these magnetic moments and the static magnetic field is not zero, they will precess around the direction of the static magnetic field. Nuclear magnetic resonance (Nuclear Magnetic Resonance, NMR) is to use radio frequency pulses to make the magnetization vector of the sample in the static magnetic field deviate from the direction of the static magnetic field, and produce precession; when the magnetization vector precesses, its magnetic field lines will cut the detection coi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N24/08
CPCG01N24/087
Inventor 蒋滨孙鹏罗凡张许杨运煌李从刚周欣刘买利
Owner INNOVATION ACAD FOR PRECISION MEASUREMENT SCI & TECH CAS
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