Quantitative Nmr Integration
Quantitative Nmr Integration - Related Videos
00:58
¹H NMR Signal Integration: Overview
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2024
The intensity of a signal, which can be represented by the area under the peak, depends on the number of protons contributing to that signal. The area under each peak is shown as a vertical line called an integral, with the integral value listed under it, as seen in the proton NMR spectrum of benzyl acetate. Each integral value is divided by the smallest integral value to obtain the ratio of the number of protons producing each signal. The ratio reveals the relative number of protons and not...
04:33
Quantitative In-Cell Hydrogen NMR Spectroscopy to Monitor Protein-Ligand Interactions
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2025
In this video, we demonstrate the in-cell nuclear magnetic resonance spectroscopy technique to study protein-ligand interactions between unlabeled overexpressed proteins and small molecules. The successful ligand-protein interaction is confirmed visually by the appearance of an additional set of peaks in the spectral region of interest that gradually replaces the original peaks.
09:24
Application and Methodology of the Non-destructive 19F Time-domain NMR Technique to Measure the Content in Fluorine-containing Drug Products
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Cited by 2 •
2017
A simple and non-destructive technique that measures the average content of drug substances in formulated drug products containing fluorine using low-field fluorine-19 (19F) time-domain (TD) nuclear magnetic resonance (NMR) is presented here. The technique can be applied to the development and manufacturing of drugs in the pharmaceutical industry.
05:57
Quantitative 31P NMR Analysis of Lignins and Tannins
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Cited by 45 •
2021
31P NMR is a powerful tool for the structural elucidation of polyphenols. This fast, easy, precise, quantitative, and highly reproducible analytical procedure, that allows for the quantification and differentiation of the different types of hydroxy, phenolic, and carboxylic groups in lignins and tannins has now become a routine analytical tool.
11:44
Spin Saturation Transfer Difference NMR (SSTD NMR): A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes
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Cited by 4 •
2016
A detailed protocol describing the SSTD NMR method is presented here to help new users apply this new method to obtain the kinetic parameters of their own systems undergoing chemical exchange.
FAQs
In quantitative NMR integration, each observed signal accumulates contribution from the nuclei represented by that resonance. Comparing integrated areas therefore compares the corresponding amounts, provided the signals are assigned and separated well enough to integrate individually. This relationship lets chemists evaluate relative composition without first preparing a compound-specific calibration curve, which is useful for mixtures and purity studies.
Relaxation time controls whether nuclei return sufficiently toward equilibrium before the next scan. If scans begin too soon, signal intensities may not reflect the underlying numbers of nuclei equally, distorting area ratios. Allowing sufficient relaxation between scans is therefore a measurement condition, not merely an instrument setting. It improves the reliability of calculated concentrations, relative amounts, and purity estimates.
A known reference or internal standard supplies the comparison needed to convert an integrated signal into an amount. Relative measurements compare analyte signals with one another, whereas absolute measurements use the known standard to establish quantity. Incorporating that reference into the NMR measurement enables concentration determination and supports quantitative analysis when no compound-specific calibration curve is available.
Overlapping resonances make it difficult to assign area to one compound or set of nuclei. Because the calculation depends on individual integrated areas, unresolved peaks can compromise mixture composition, purity, or reaction measurements. Chemists therefore favor spectra in which relevant signals can be distinguished and integrated separately before interpreting the resulting numerical comparisons.
A basic workflow begins by preparing the sample with a known reference or internal standard, acquiring NMR scans with sufficient relaxation, identifying relevant resonances, and integrating well-resolved signals. The resulting areas are compared either with one another or with the standard’s known amount. This sequence converts spectral intensity information into relative composition, concentration, or purity evidence for a chemical sample.
Quantitative NMR integration supports purity and concentration measurements because area comparisons link a sample signal to either other analyte signals or a known reference. In a purity assessment, distinguishable signals can reveal the proportion of the desired compound relative to measured components. For concentration work, the reference provides the basis for converting the comparison into an amount in the sample.
Reaction monitoring can use changes in integrated, well-resolved signals to assess the relative amounts of chemical components as a sample changes. Mixture analysis similarly benefits when relevant resonances can be distinguished and compared. Minimal sample preparation and the absence of compound-specific calibration curves make the approach a useful complement to chromatographic and other spectroscopic methods in chemistry.