Related Experiment Video
Updated: Jun 24, 2026

NMR Spectroscopy as a Robust Tool for the Rapid Evaluation of the Lipid Profile of Fish Oil Supplements
Published on: May 1, 2017
Determination of relative response factors for chromatographic investigations using NMR spectrometry
Gregory K Webster1, Ian Marsden, Cynthia A Pommerening
1Global Research & Development, Abbott Laboratories, 100 Abbot Park Road, Abbott Park, IL 60064-3500, USA. gregory.webster@abbott.com
Abstract:
In the absence of suitable reference materials for impurity quantitation, laboratories have developed techniques using mass detectors such as the chemical luminescence detector (CLND) and the charged aerosol detector (CAD) to normalize the UV response of each impurity of interest by their molar ratios and thus generate relative response factors without requiring isolated and purified compound-specific standards. While effective, these detectors are limited in response and are effective only with specific mobile phase requirements. Nuclear magnetic resonance (NMR) spectrometry has the advantage of allowing the universal detection of protons while not suffering from the limitations observed for CLND, CAD, and other common detectors. The determination of relative response factors using NMR has been successfully applied to several LC methods. An overview of this technique and representative results are presented.
Related Concept Videos
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
¹H NMR Signal Integration: Overview
NMR Spectrometers: Resolution and Error Correction
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
¹H NMR: Complex Splitting
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.

