Chempacker LLC, San Jose, California, USA.
Magn Reson Chem. 2021 Aug;59(8):757-791. doi: 10.1002/mrc.5135. Epub 2021 Jan 31.
The CRAFT (Complete Reduction to Amplitude Frequency Table) technique, based on Bayesian analysis approach, converts FID and/or interferogram (time domain) to a frequency-amplitude table (tabular domain) in a robust, automated, and time-efficient fashion. This mini review/perspective presents an introduction to CRAFT as a processing workflow followed by a discussion of several practical 1D and 2D examples of its applicability and associated benefit. CRAFT provides high quality quantitative results for complex systems without any need for conventional preprocessing steps, such as phase and baseline corrections. Two-dimensional time domain data are typically truncated, particularly in the evolution dimension, and conventional processing after zero-filling and t -matched apodization masks potentially available peak resolution. The line broadening introduced by extensive zero-filling and severe apodization functions leads to the lack of clear resolution of cross peaks. CRAFT decimation of interferograms, on the other hand, requires minimal or no apodization prior to extraction of the NMR parameters and significantly improves the spectral linewidth of the cross peaks along F dimension compared to conventional (FT) processing. The tabular representation of the CRAFT2d cross peaks information can be visualized in a variety of frequency domain formats for conventional spectral interpretation as well as quantitative applications. A simple workflow to generate in silico oversampled interferogram (iSOS) is presented, and its potential benefit in CRAFT decimation of highly crowded 2D NMR is demonstrated. This report is meant as a collective thesis to present a potentially new paradigm in data processing that questions the need for hitherto unchallenged preprocessing steps, such as phase and baseline correction in 1D and zero-fill/severe apodization in 2D.
CRAFT(全振幅频率表还原)技术基于贝叶斯分析方法,以稳健、自动化和高效的方式将 FID 和/或干涉图(时域)转换为频率-振幅表(表格域)。本篇简要综述/观点介绍了 CRAFT 作为一种处理工作流程,随后讨论了其在几个 1D 和 2D 应用实例中的适用性和相关优势。CRAFT 为复杂体系提供了高质量的定量结果,而无需任何常规预处理步骤,例如相位和基线校正。二维时域数据通常会被截断,特别是在演化维度,而传统的后处理,如零填充和 t 匹配的窗函数,可能会影响到峰分辨率。广泛的零填充和严重的窗函数会导致线宽变宽,从而使交叉峰的分辨率不清晰。相比之下,CRAFT 对干涉图的抽取不需要在提取 NMR 参数之前进行最小或无需窗函数处理,并且可以显著提高 F 维度上交叉峰的光谱线宽,优于传统(FT)处理。CRAFT2d 交叉峰信息的表格表示可以以各种频率域格式可视化,用于常规光谱解释以及定量应用。本文提出了一种生成虚拟过采样干涉图(iSOS)的简单工作流程,并展示了其在高度拥挤的 2D NMR 中 CRAFT 抽取中的潜在优势。本文旨在作为一篇综合论文,提出一种新的数据处理范例,质疑迄今未受到挑战的预处理步骤(如 1D 中的相位和基线校正以及 2D 中的零填充/严重窗函数)的必要性。