%0 Journal Article
%T Baseline Correction for NMR Spectroscopic Metabolomics Data Analysis
%A Yuanxin Xi
%A David M Rocke
%J BMC Bioinformatics
%D 2008
%I BioMed Central
%R 10.1186/1471-2105-9-324
%X We tested this method on 1D NMR spectra with different forms of baseline distortions, and demonstrated that it is effective for both regular 1D NMR spectra and metabolomics spectra with over-crowded peaks.Compared with the automatic baseline correction function in XWINNMR 3.5, the penalized smoothing method provides more accurate baseline correction for high-signal density metabolomics spectra.Baseline distortions in 1D NMR spectra are mainly caused by the corruption of the first few data points in FID (free induction decay). These corrupted data points add low frequency modulations in the Fourier-transformed spectrum, and thus formed the distorted baseline. Correction of these distortions is a necessary step in NMR spectra data processing because they offset the intensity values and result in inaccuracy in peak assignment and quantification. These errors could be critical in the study of metabolomics, which involves many small but statistically significant peaks that are sensitive to baseline distortions. Incorrect quantification of these peaks may result in failures in detection of important metabolites or identifying potential biomarkers.Existing automatic baseline distortion correction methods fall into two categories: time domain correction and frequency domain correction [1-9]. Time domain correction methods reconstruct the corrupted data points in FID to reduce the low frequency modulation [6-8]. Frequency domain correction methods construct baseline curves in the spectra directly, and subtract these baseline curves to remove the distortion [1-5]. These methods have been implemented in commercial software and hand-written programs for NMR data processing. Usually a combination of both time and frequency domain methods are applied to achieve better correction. In comparison, time domain methods provide general correction for FID and frequency domain methods provide more detailed correction on the spectrum itself. For processing a specific kind of NMR spectra,
%U http://www.biomedcentral.com/1471-2105/9/324