Optimization and Automation of Quantitative NMR Data Extraction

Abstract

NMR is routinely used to quantitate chemical species. The necessary experimental procedures to acquire quantitative data are well-known, but relatively little attention has been applied to data processing and analysis. We describe here a robust expert system that can be used to automatically choose the best signals in a sample for overall concentration determination and determine analyte concentration using all accepted methods. The algorithm is based on the complete deconvolution of the spectrum which makes it tolerant of cases where signals are very close to one another and includes robust methods for the automatic classification of NMR resonances and molecule-to-spectrum multiplets assignments. With the functionality in place and optimized, it is then a relatively simple matter to apply the same workflow to data in a fully automatic way. The procedure is desirable for both its inherent performance and applicability to NMR data acquired for very large sample sets.

Quantitative NMR Studies of Multiple Compound Mixtures

“…Robust data processing and analysis procedure have been used to automatically extract the qNMR data [249]. To accurately obtain the peak areas, spectra can be deconvoluted and peak areas are automatically determined for quantification, preferably in combination with algorithms for their identification based on the standard NMR spectra base or database.…”

Automated Processing and Statistical Analysis of NMR spectra obtained from Arabidopsis thaliana Extracts

“…Metabolite analysis, reaction monitoring/following or other mixture analysis can produce vast amounts of complex spectra, which are difficult to analyze with 5 traditional NMR processing software, as they are designed from the viewpoint of smallmolecule analysis. To accommodate these needs, features aimed for mixture analysis and automation have been incorporated into commercial processing software (Agilent/Varian CRAFT [1], Mnova GSD and qNMR [2], Bruker Biospin AMIX and IconNMR). The rising popularity of utilizing NMR for metabolomics has also spawned many commercial 10 and free tools suited for different stages and aspects of metabolite analysis: NMR Suite (Chenomx Inc. [3,4]), rNMR [5], BATMAN [6,7], Pathomx [8] and others [9,10], with publicly available databases [11,12] and even web-applications available [13,14].…”

“…Other techniques like Agilent CRAFT [1] based on Bayesian fitting of signals directly to the FID data or Mnova GSD [2] can in principle decompose the spectrum into frequency-intensity pairs in full automation, but do not take into account or combine signals resulting from the same compound. This kind of data requires further refinement or filtering of the data in non-targeted analysis, and the real-world use of these techniques 105 applied for complex mixtures seems to be limited.…”

Accurate quantification of modified cyclic peptides without the need for authentic standards

“…Sulphur has been successfully used for the quantification of proteins and peptide in biological samples by coupling the ICP-MS to different chromatographic systems. [37][38][39][40] NMR produces a signal for any species that will have an area that is proportional to its concentration. 40 Complex mixtures can be analyzed by NMR which provides the concentration of the chemical components in a mixture, hence allowing quantification of species for metabolomic and related studies.…”

“…[37][38][39][40] NMR produces a signal for any species that will have an area that is proportional to its concentration. 40 Complex mixtures can be analyzed by NMR which provides the concentration of the chemical components in a mixture, hence allowing quantification of species for metabolomic and related studies. [41][42] Proton NMR quantification (qNMR) by ERETIC is a non-destructive and rapid way of providing accurate analyte concentrations 43 by using an indirect internal reference signal that represents a known concentration.…”