Fast and Accurate Quantitative Metabolic Profiling of Body Fluids by Nonlinear Sampling of ¹H–¹³C Two-Dimensional Nuclear Magnetic Resonance Spectroscopy

Abstract

Two-dimensional (2D) nuclear magnetic resonance (NMR) methods have shown to be an excellent analytical tool for the identification and characterization of statistically relevant changes in low-abundance metabolites in body fluid. The advantage of 2D NMR in terms of minimized ambiguities in peak assignment, aided in metabolite identifications and comprehensive metabolic profiling comes with the cost of increased NMR data collection time; making it inconvenient choice for routine metabolic profiling. We present here a method for the reduction in NMR data collection time of 2D (1)H-(13)C NMR spectroscopy for the purpose of quantitative metabolic profiling. Our method combines three techniques; which are nonlinear sampling (NLS), forward maximum (FM) entropy reconstruction, and J-compensated quantitative heteronuclear single quantum (HSQC) (1)H-(13)C NMR spectra. We report here that approximately 22-fold reduction in 2D NMR data collection time for the body fluid samples can be achieved by this method, without any compromise in quantitative information recovery of various low abundance metabolites. The method has been demonstrated in standard mixture solution, native, and lyophilized human urine samples. Our proposed method has potential to make quantitative metabolic profiling by 2D NMR as a routine method for various metabonomic studies.

Advances in NMR-Based Metabolomics

“…For example, nonlinear sampling and forward maximum entropy reconstruction offer significant reduction in data acquisition times (66,67). The method was demonstrated in an analysis of urinary metabolites (68). A method that combines nonlinear sampling, forward maximum entropy reconstruction, and J-compensated 1 H-13 C HSQC spectra was shown to achieve a 22-fold reduction in time without the loss of any quantitative information.…”

Quantitative NMR Studies of Multiple Compound Mixtures

“…The second strategy is 2D-or higherdimensional NMR techniques. For example, 1 H-13 C HSQC [81], 2D J-resolved NMR (JRES) [82,92], 2D 1 H incredible natural-abundance double-quantum transfer experiment (INADEQUATE) [85], and 1 H-1 H correlation spectroscopy (COSY) [84] have been employed to quantitative metabolomics. However, conventional quantitative 2D NMR experiments usually require long experimental time (usually from 30 min to several hours).…”

“…To overcome this limitation, spatially encoded pulse sequence [84] and nonlinear sampling schemes [81] have been incorporated into quantitative 2D NMR, which have been successfully applied in metabolomics studies.…”

Accurate determination of ethanol in water by qNMR: Validation and uncertainty assessment

“…qNMR applications is now widely available in various fields, such as drug industry [1], manufacturing of reference materials [2], food analyses [3,4] and metabolite determination in human body fluids [5][6][7][8][9][10][11]. Moreover, applications of qNMR involve determination of purity of a compound and amount and concentration of a sample inside a matrix.…”