Jeol Ltd.

Muneki Ohuchi

Haruo Seto

Kazuo Furihata

Osamu Kamo

Soukichi Uchida

Kazuhiro Matsushita

There is disclosed a method of precisely correcting the phase of a two-dimensional NMR spectrum along the two axes. First, a first phase train is applied to a sample. After an evolution period of t.sub.1, a second pulse train is applied. Then, the free induction decay signal emanating from the sample is detected during a detection period of t.sub.2, using a quadrature detection system. This process is repeated with different values of t.sub.1. Thus, a complex NMR spectrum S.sub.1 (t.sub.1, t.sub.2) is obtained. Subsequently, the sample is excited with a pulse sequence which is similar to the first-mentioned pulse sequence except that the second pulse is shifted in phase by 90.degree./n (n is a natural number) with respect to the second pulse of the first-mentioned pulse sequence. The resulting free induction decay signal is detected. This process is repeated with the same number of different values of t.sub.1 as the values of t.sub.1 used in the first set of measurements. Thus, a complex NMR spectrum S.sub.2 (t.sub.1, t.sub.2) is derived. The spectra S.sub.1 (t.sub.1, t.sub. 2) and S.sub.2 (t.sub.1, t.sub.2) are subjected to complex Fourier transformation with respect to the axis t.sub.2. Then, the imaginary part of S.sub.1 (t.sub.1, F.sub.2) and the real part of S.sub.2 (t.sub.1, F.sub.2) are interchanged to give rise to Fourier-transformed spectra S.sub.1 '(t.sub.1, F.sub.2) and S.sub.2 '(t.sub.1, F.sub.2), which are then subjected to complex Fourier transformation with respect to the axis t.sub.1. The phase is corrected along one of the axes. The imaginary part of S.sub.1 '(F.sub.1, F.sub.2) and the real part of S.sub.2 (F.sub.1, F.sub.2) are interchanged. Then, the phase is corrected along the other axis.

Phase correction method in two-dimensional NMR spectroscopy

A two-dimensional nuclear magnetic resonance spectrometry which comprises the following steps to facilitate phase correction:

Two-dimensional nuclear magnetic resonance spectrometry

The present invention provides a nuclear magnetic resonance spectroscopy that permits one to see changes in spectra without the use of long-range coupling even if the obtained resonance lines split into complex multiplet patterns. The spectrometry comprises the steps of: (a) applying a pulse train of radio-frequency irradiation to a nucleus under observation; (b) applying weak radio-frequency irradiation having a frequency equal to the resonance frequency either of an unobserved nucleus coupled to the observed nucleus or of the observed nucleus in synchronism with the application of the pulse train; (c) receiving the free induction decay signal produced after the application of the pulse train and storing it in a memory; (d) applying a pulse train of radio-frequency irradiation to the observed nucleus; (e) receiving the free induction decay signal produced after the application of the pulse train in step (d) and either adding it to the free induction decay signal stored in step (c) or substracting it from the previously stored signal; and (f) taking the Fourier transform of the free induction decay signal obtained by the arithmetic operation in step (e).

Nuclear magnetic resonance spectroscopy

A nuclear magnetic resonance spectrometry is disclosed in which a 90.degree. pulse and a 180.degree. pulse are applied to nuclei under observation at a time interval of t. Then, the resulting echo signal is observed after a period of t. Either a strong 90.degree. pulse of strong RF waves are applied to nuclei that are not observed. The strong RF waves decouple the nuclei not observed over a broad range. The application of the strong 90.degree. pulse or RF waves is initiated in synchronism with the 180.degree. pulse. The application of the RF waves are terminated before the beginning of the observation of the echo signal. The observation made in this way makes it possible to obtain spectra of quaternary carbons, the spectra including the information about long-range coupling.

Nuclear magnetic resonance spectrometry

The present invention relates to an improved nuclear magnetic resonance spectroscopy for selectively detecting multiple quantum transitions of a selected order, the transitions taking place in a sample containing a system of rotating magnetic resonators. The spectrometry comprises the steps of: (a) applying a pulse train to the resonators, the pulse train consisting of RF pulses in which at least one pulse is .phi. degrees out of phase with the last pulse; (b) detecting the free induction decay signal emanating from the resonators for a period of time t2 after the application of the pulse train, using two channels of detecting system which are 90.degree. out of phase with each other, and storing it in a memory. The steps are repeated changing the values of the evolution time t1, resetting the values of .phi., and adding 90.degree., 180.degree., and 270.degree. to all values of .phi.. The data are combined and converted to frequency domain by double Fourier transformation with respect to t1 and t2.

Nuclear magnetic resonance spectroscopy for selective detection of

A method and apparatus for nuclear magnetic resonance spectroscopy is disclosed which expands the decoupling bandwidth. In the method, a pulse train containing a series of radiofrequency pulses joined without interval is applied repeatedly to a sample, each radiofrequency pulse being phased at 0.degree., 90.degree., 180.degree., or 270.degree., and the radiofrequency carrier of the pulse train is reversed in phase at the interval longer than the repetitive cycle of the pulse train asynchronously with the repetition of application of the pulse train.

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Tokyo, Japan

Muneki Ohuchi