Quantitative Nuclear Magnetic Resonance (qNMR) Analysis

qNMR analysis, for analytical quantification.

Intertek NMR laboratories provide qNMR (Quantitative Nuclear Magnetic Resonance Spectroscopy) analysis applications such as quality control, drug impurity analysis, and metabonomics in agrochemicals, chemicals, plastics processing and the pharmaceutical industry.

qNMR is a flexible analytical tool for quantification of content or purity of organic substances. The method is based on a direct comparison of NMR signal intensities of the compound of interest with reference signals. The reference signal can be derived from any internal reference compound with known structure and purity. In case of impurity analysis, the signals of the main compound often can be used as a reference.

Depending on the respective analytical requirement qNMR can be applied to all NMR active nuclei like 1H, 13C, 31P or 19F. qNMR offers advantages over other analytical techniques and can be more precise and accurate than standard chromatographic methods. The development and validation of a method is relatively simple due to the underlying physical process, and the proportionality and linearity of the concentration of analyte and reference. The method is robust and will integrate efficiently with routine analysis. Typically, no special sample preparation is necessary. The sample is simply dissolved in a suitable NMR solvent.

31P and 19F qNMR show high selectivity and remarkable sensitivity. The significantly higher sensitivity 1H qNMR technique enables detection limits down to the ppm range. In many cases, it is a good alternative to gas chromatography (GC) or high-pressure liquid chromatography (HPLC). Examples of this are validation of reference compounds and determination of residual solvent or water in a sample.