Discrete and Continuous Spin–Spin Relaxation Rate Distributions Derived from CPMG NMR Response Curves: a Comparative Analysis Exemplified by Water in Meat
- Авторлар: Hansen E.1, Zhu H.1,2,3
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Мекемелер:
- Department of Chemistry, University of Oslo
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences
- Nortura SA
- Шығарылым: Том 47, № 11 (2016)
- Беттер: 1255-1272
- Бөлім: Original Paper
- URL: https://journals.rcsi.science/0937-9347/article/view/247574
- DOI: https://doi.org/10.1007/s00723-016-0828-y
- ID: 247574
Дәйексөз келтіру
Аннотация
The spin–spin relaxation rate distribution of water in a porcine longissimus dorsi muscle was derived from an inverse integral transformation of the proton CPMG (Carr–Purcell–Meiboom–Gill) NMR (nuclear magnetic resonance) signal at each hour during a 49 h drip period. This “continuous (C)” relaxation rate distribution was found to be excellently represented by an empirical peak function, characterized by three parameters: a peak width, an average relaxation rate, and a skewness parameter, which enable the distribution to be quantitatively defined. In addition, the same CPMG response was fitted to a sum of three single-exponential decay functions, denoted a “discrete (D)” relaxation rate model. The analysis shows that when the fraction of the slow relaxation component \(f_{2}^{\text{C}}\) from the continuous model is close to 5 %, which is a rather typical value, the mean relaxation rate \(\bar{R}_{22}^{\text{D}}\) from the discrete model becomes larger than the corresponding relaxation rate \(\bar{R}_{22}^{\text{C}}\) from the continuous model by nearly 25 % and \(f_{2}^{\text{D}}\) becomes larger than \(f_{2}^{\text{C}}\) by more than 75 %. Likewise, when \(f_{2}^{\text{C}}\) approaches 2.5 %, \(\bar{R}_{22}^{\text{D}}\) becomes larger than \(\bar{R}_{22}^{\text{C}}\) by more than 75 % and \(f_{2}^{\text{D}}\) becomes larger than \(f_{2}^{\text{C}}\) by more than a factor of 3 which are supported by model simulations. The relative quality and goodness of the two different relaxation rate models are discussed. Finally, the number of transients needed to obtain a preset error in relaxation rate and/or mole fraction was determined by model simulation.
Негізгі сөздер
Авторлар туралы
Eddy Hansen
Department of Chemistry, University of Oslo
Хат алмасуға жауапты Автор.
Email: e.w.hansen@kjemi.uio.no
Норвегия, Blindern, Oslo, 0315
Han Zhu
Department of Chemistry, University of Oslo; Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences; Nortura SA
Email: e.w.hansen@kjemi.uio.no
Норвегия, Blindern, Oslo, 0315; Ås, 1432; Lørenveien 37, Økern, Oslo, 0585