Recently, a new multivariate analysis tool was developed to resolve mixture data sets, where the contributions ('concentrations') have an exponential profile. The new approach is called DECRA (direct exponential curve resolution algorithm). DECRA is based on the generalized rank annihilation method
Effect of non-exponential and multi-exponential decay behavior on the performance of the direct exponential curve resolution algorithm (DECRA) in NMR investigations
✍ Scribed by Todd M. Alam; M. Kathleen Alam
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 193 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0886-9383
- DOI
- 10.1002/cem.826
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✦ Synopsis
Abstract
The effect of non‐exponential and multi‐exponential decay or relaxation behavior on the performance of the direct exponential curve resolution algorithm (DECRA) is investigated through a series of numerical simulations. Three different combinations of decay or relaxation behavior were investigated through DECRA analysis of simulated pulse gradient spin echo (PGSE) NMR diffusion spectra that contained the combination of two individual components. The diffusion decay behavior of one component was described by a single‐exponential decay, while the second component was described by either (1) a multi‐exponential decay, (2) a decay behavior described by the empirical Kohlrausch–Williams–Watts (KWW) relation or (3) a multi‐exponential decay behavior correlated with variations in the NMR spectral line shape. The magnitudes and types of errors produced during the DECRA analysis of spectral data with deviations from a pure single‐exponential decay behavior are presented. It is demonstrated that the deviation from single‐exponential decay impacts the resulting calculated line shapes, the calculated relative concentrations and the quantitative estimation of the decay or relaxation time constants of both components present in the NMR spectra. Copyright © 2004 John Wiley & Sons, Ltd.
📜 SIMILAR VOLUMES
Antalek and Windig recently presented a fast method to resolve a series of NMR mixture spectra, where the contribution of the components varies with a decaying exponential [B. Antalek and W. Windig, J. Am. Chem. Soc. 118, 10,331-10,332 (1996); W. Windig and B. Antalek, Chemom. Intell. Lab. Syst. 37,