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Application of CRAFT (complete reduction to amplitude frequency table) in nonuniformly sampled ( NUS ) 2 D NMR data processing
Author(s) -
Krishnamurthy Krish,
Hari Natarajan
Publication year - 2018
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.4664
Subject(s) - apodization , amplitude , algorithm , chemistry , reduction (mathematics) , frequency domain , sampling (signal processing) , computer science , optics , physics , mathematical analysis , mathematics , geometry , detector
The recently published CRAFT (complete reduction to amplitude frequency table) technique converts the raw FID data (i.e., time domain data) into a table of frequencies, amplitudes, decay rate constants, and phases. It offers an alternate approach to decimate time‐domain data, with minimal preprocessing step. It has been shown that application of CRAFT technique to process the t 1 dimension of the 2D data significantly improved the detectable resolution by its ability to analyze without the use of ubiquitous apodization of extensively zero‐filled data. It was noted earlier that CRAFT did not resolve sinusoids that were not already resolvable in time‐domain (i.e., t 1 max dependent resolution). We present a combined NUS–IST–CRAFT approach wherein the NUS acquisition technique (sparse sampling technique) increases the intrinsic resolution in time‐domain (by increasing t 1 max), IST fills the gap in the sparse sampling, and CRAFT processing extracts the information without loss due to any severe apodization. NUS and CRAFT are thus complementary techniques to improve intrinsic and usable resolution. We show that significant improvement can be achieved with this combination over conventional NUS–IST processing. With reasonable sensitivity, the models can be extended to significantly higher t 1 max to generate an indirect‐DEPT spectrum that rivals the direct observe counterpart.