Nuclear magnetic resonance (NMR) spectrometry is a well established laboratory technique for the characterisation of organic compounds, and it has a number of features of potential benefit for on-line or at-line process applications. In principle, the technique is capable of analysing solid, liquid or gaseous samples, in a non-invasive way, to provide highly specific chemical identification. The compositional analysis of flowing liquids is the most obvious potential application in the chemical plant, extending developments in LC-NMR.

In comparison with other techniques, FT-NMR spectrometry has been largely overlooked for on-line process analysis, mainly because of the perceived high cost and complexity of the instrumentation. However, recent advances have made possible the use of permanent magnets in small, high-resolution, instruments capable of measuring 1H, 19F, and 31P NMR spectra. This technology could form the basis of a process instrument capable of analysing flowing liquids or gases. The degree of specificity to 1H, 19F and 31P containing groups in either simple or complex molecules could be of considerable advantage in process applications where hydrocarbon, fluorocarbon and catalytic compounds need to be monitored.