New and rapid pulse sequences for two-dimensional D-T-1 correlation measurements

Autor(es)

Montrazi, Elton Tadeu ^[1] ; Monaretto, Tatiana ^[2] ; Bonagamba, Tito Jose ^[1] ; Colnago, Luiz Alberto ^[3]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sao Carlos Inst Phys, POB 369, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Sao Paulo, Sao Carlos Inst Chem, POB 780, BR-13560970 Sao Carlos, SP - Brazil

^[3] Embrapa Instrumentat, POB 741, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF MAGNETIC RESONANCE; v. 315, JUN 2020.
• Citações Web of Science: 0

Resumo

Longitudinal relaxation time (T-1), transverse relaxation time (T-2) and diffusion coefficient (D) values have been widely used for the characterizations of materials using low field Time Domain Nuclear Magnetic Resonance (TD-NMR). Each parameter can be determined using one-dimensional techniques or their values and correlations by multi-dimensional experiments such as T-1-T-2, D-T-2, and T-1-D-T-2. In this work, we studied four D-T-1 sequences for TD-NMR combining Stejskal-Tanner Pulse Gradient Spin Echo (PGSE) diffusion measurement with Inversion-Recovery (IR), Saturation-Recovery (SR), Small-Angle Continuous Wave Free Precession (CWFP-T-1) and Small-Angle Flip-Flop (SAFF) for T-1 measurement. The results show that rapid D-T-1 measurements can be obtained with single shot CWFP-T-1 and SAFF sequences. The two sequences were two and eight time fast than sequences based on SR and IR, respectively. Although the two fast sequences yield low signal-to-noise ratio signal, they can be as fast as the traditional D-T-2 experiment, or even faster, because it is not necessary to wait a recycle delay of 5 T-1. Another advantage of the CWFP-T-1 and SAFF methods, when compared to the one based on SR or CPMG (for D-T-2) are the low specific absorption rate (SAR) of these sequences due the low flip angles in the sequences, that reduces the sample heating problem. These sequences were initially studied using phantom samples. They also were used to study plant tissues to observe the anisotropic diffusion in asparagus. Therefore, they can be useful methods for practical application in TD-NMR. (C) 2020 Elsevier Inc. All rights reserved. (AU)

• Processo FAPESP: 19/13656-8 - Desenvolvimento e aplicações da ressonância magnética nuclear em produtos e processos de interesse agropecuário
• Beneficiário: Luiz Alberto Colnago
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 09/54880-6 - Manipulação de spins nucleares através de técnicas de ressonância magnética e quadrupolar nuclear
• Beneficiário: Tito José Bonagamba
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 17/12864-0 - Avaliação do efeito do campo magnético dos espectrômetro de RMN em reações químicas monitoradas in situ
• Beneficiário: Luiz Alberto Colnago
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 12/00380-5 - Avaliação da resistência à fadiga cíclica de sistemas rotatórios e recíprocos
• Beneficiário: Idomeo Bonetti Filho
• Modalidade de apoio: Auxílio à Pesquisa - Regular