title: Real-time bilinear rotation decoupling in absorptive mode J-spectroscopy: Detecting low-intensity metabolite peak close to high-intensity metabolite peak with convenience.
abstract: "Pure shift" NMR spectra display singlet peak per chemical site. Thus, high resolution is offered at the cost of valuable J-coupling information. In the present work, real-time BIRD (BIlinear Rotation Decoupling) is applied to the absorptive-mode 2D J-spectroscopy to provide pure shift spectrum in the direct dimension and J-coupling information in the indirect dimension. Quite often in metabolomics, proton NMR spectra from complex bio-fluids display tremendous signal overlap. Although conventional J-spectroscopy in principle overcomes this problem by separating the multiplet information from chemical shift information, however, only magnitude mode of the experiment is practical, sacrificing much of the potential high resolution that could be achieved. Few J-spectroscopy methods have been reported so far that produce high-resolution pure shift spectrum along with J-coupling information for crowded spectral regions. In the present work, high-quality J-resolved spectrum from important metabolomic mixture such as tissue extract from rat cortex is demonstrated. Many low-intensity metabolite peaks which are obscured by the broad dispersive tails from high-intensity metabolite peaks in regular magnitude mode J-spectrum can be clearly identified in real-time BIRD J-resolved spectrum. The general practice of removing such spectral overlap is tedious and time-consuming as it involves repeated sample preparation to change the pH of the tissue extract sample and subsequent spectra recording.
authors.affiliation: Centre of Biomedical Research (Formerly Centre of Biomedical Magnetic Resonance), SGPGIMS Campus, Raebareli Road, Lucknow 226014, India.
authors.forename: Ajay
authors.initials: A
authors.lastname: Verma
authors.affiliation: Centre of Biomedical Research (Formerly Centre of Biomedical Magnetic Resonance), SGPGIMS Campus, Raebareli Road, Lucknow 226014, India. Electronic address: bikashbaishya@gmail.com.
authors.forename: Bikash
authors.initials: B
authors.lastname: Baishya
mesh_terms: D000465:Algorithms; D000818:Animals; D001921:Brain / Q000378:metabolism*; D003199:Computer Systems; D055442:Metabolome / Q000502:physiology*; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D051381:Rats; D015203:Reproducibility of Results; D012399:Rotation; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
keywords: Complex mixture analysis; J-resolved NMR; Pure shift NMR; Real-time BIlinear Rotation Decoupling (BIRD)