Method and apparatus for obtaining pure-absorption two-dimensional lineshape data for multidimensional NMR spectroscopy using switched acquisition time gradients

Claim 5

In multidimensional spectroscopy of a molecular system, a method of obtaining a frequency-domain spectra of NMR spectroscopy data S(ω 1 ,ω 2 where ω 1 and ω 2 are two independent frequency variables) from a single acquisition of time-domain signals S(t 1 ,t 2 where t 1 and t 2 are two independent time variables from coherence transfer pathways using switched acquisition time gradients comprising the steps of a) placing said molecular system in a static magnetic field, b) applying a time sequence of rf and gradient pulses to said molecular system whereby spins are prepared in a coherent coherence-order-labeled non-equilibrium state, c) applying a focusing gradient to said molecular system for selecting a first coherence transfer pathway for detecting time domain data, d) quadrature detecting time domain data at a first data sampling point from said first coherence transfer pathway, e) applying a first refocusing gradient to said molecular system for selecting a second coherence transfer pathway, f) quadrature detecting time domain data at a first data sampling point from said second coherence transfer pathway, g) applying a second refocusing gradient to said molecular system for selecting said first coherence transfer pathway, h) quadrature detecting data at a second data point in said first coherence transfer pathway, i) repeating steps e) through h) for detecting data at other data sampling points in said first coherence transfer pathway and said second coherence transfer pathway, j) transforming all data obtained by quadrature detection into first Fourier transformed signals at each data sampling period, said signals having real and imaginary components which modulate as sine and cosine functions with respect to t 1 , k) combining real (ω 2 ) cosine (t 1 ) components and imaginary (ω 2 ) sine (t 1 ) components at each data sampling to construct a complex data set, and transforming each complex data set to obtain a frequency-domain spectrum at each data sampling point.

Claim 6

In multidimensional spectroscopy of a molecular system, a method of obtaining a frequency-domain spectra of NMR spectroscopy data S(ω 1 ,ω 2 where ω 1 and ω 2 are two independent frequency variables) from a single acquisition of time-domain signals S(t 1 ,t 2 where t 1 and t 2 are two independent time variables from coherence transfer pathways using switched acquisition time gradients comprising the steps of a) placing said molecular system in a static magnetic field, b) applying a time sequence of rf and gradient pulses to said molecular system whereby spins are prepared in a coherent coherence-order-labeled non-equilibrium state, c) applying a focusing gradient to said molecular system for selecting a first coherence transfer pathway for detecting time domain data, d) quadrature detecting time domain data at a first data sampling point from said first coherence transfer pathway, e) applying a first refocusing gradient to said molecular system for selecting a second coherence transfer pathway, f) quadrature detecting time domain data at a first data sampling point from said second coherence transfer pathway, g) applying a second refocusing gradient to said molecular system for selecting said first coherence transfer pathway, h) quadrature detecting data at a second data point in said first coherence transfer pathway, i) repeating steps e) through h) for detecting data at other data sampling points in said first coherence transfer pathway and said second coherence transfer pathway, j) transforming all data obtained by quadrature detection into first Fourier transformed signals at each data sampling period, said signals having real and imaginary components which modulate as sine and cosine functions with respect to t 1 , k) combining real (ω 2 ) cosine (t 1 ) components and imaginary (ω 2 ) sine (t 1 ) components at each data sampling to construct a complex data set, and transforming each complex data set to obtain a frequency-domain spectrum at each data sampling point.