T₁ relaxation measurement with solvent suppression

Abstract

Three solvent-suppression pulse sequences of varying complexity were incorporated into the standard inversion recovery pulse program and experimentally evaluated. The least complex suppression sequence involves a composite 90 degrees pulse. A more complex sequence utilizes an excitation sculpting sequence requiring pulsed field gradients, and the most complex sequence incorporates an excitation sculpting sequence with selective rf pulses and gradient pulses. The quality of the spectral data and the accuracy of T(1) measurements of the investigated suppression schemes were evaluated using three aqueous samples with increasing proton content in the water solvent, i.e. by volume 100% D(2)O, 80/20% D(2)O/H(2)O, and 100% H(2)O. For lines removed from the water resonance the T(1) values were generally very consistent between all pulse sequences tested. For lines less than about 200 Hz from the water signal the T(1) measurements become less reliable but are still possible for most of the tested pulse programs.

Identification and quantification of water‐soluble metabolites by cryoprobe‐assisted nuclear magnetic resonance spectroscopy applied to microbial fermentation

“…We applied a slightly modified version of the excitation sculpting (ES) sequence that removes the water from the process and allows smooth and precise measurement of T1. Our method is closely related to variants published recently [23] ; however, we fully avoided presaturation of the water signal by applying an effective 360…”

T2 relaxation measurement with solvent suppression and implications to solvent suppression in general

“…The integration ranges for each of the nine signals were chosen as in our previous T 1 study where we were using the same chemical sample system. [1] The T 2 values from Sample 1 are summarized in Table 1. As one might expect from the qualitative assessment of the waterfall plots, agreement with the Standard CPMG pulse program is the least for Signals 1 and 2, where the best agreement is observed for the Just Presat pulse program, which we understand to be a result of having the narrowest gap in the excitation profile in www.interscience.wiley.com/journal/mrc The same trends are also observed for the T 2 values obtained from Samples 2 and 3, which are summarized in Tables 2 and 3, respectively.…”

“…[1] Despite that solvent suppression has been a continuing topic of scrutiny in NMR spectroscopy [2 -6] and a number of reviews have appeared on this subject, [7 -10] literature on solvent suppression during relaxation measurements is virtually absent. Besides our previous report, [1] we are aware of only one other study [11] on solvent suppression during T 1 relaxation measurements and none for solvent suppression during T 2 relaxation measurements.…”

“…[1] Despite that solvent suppression has been a continuing topic of scrutiny in NMR spectroscopy [2 -6] and a number of reviews have appeared on this subject, [7 -10] literature on solvent suppression during relaxation measurements is virtually absent. Besides our previous report, [1] we are aware of only one other study [11] on solvent suppression during T 1 relaxation measurements and none for solvent suppression during T 2 relaxation measurements. Hence, it seems worthwhile to expand our studies with respect to solvent suppression during T 2 relaxation measurements, which would also be useful for our own current research interests focusing on industrial aqueous surfactant formulations where many of them are premixed with H 2 O.…”

Nuclear Magnetic Resonance: Basic Principles and Liquid State Spectroscopy

“…Such solvent suppression pulse sequences have also been incorporated into many common 1D and 2D experiments. In fact, the authors have incorporated them recently in relaxation measurements (Hoffmann et al, 2008b. For an in-depth coverage on the issues related to solvent suppression in NMR spectroscopy, the interested reader is referred to a recent review (Zheng and Price, 2010).…”