Pulsed field gradient (PFG) NMR spectroscopy: An effective tool for the analysis of mixtures of lubricating oil components

Abstract

AbstractIn the presently reported work, the multinuclear two‐dimensional (2D) diffusionordered nuclear magnetic resonance (NMR) spectroscopy (DOSY) technique based on the pulsed field gradient (PFG) has been used in experiments to analyse mixtures of lubricating oil components. One‐dimensional (1D) PFG experiments have also been used to simplify and edit the NMR spectra of the mixtures. Such experiments provide a clean spectrum of the highest molecular weight (slower diffusing) component by eliminating the signals of lower molecular weight (faster diffusing) components, without any prior physical separation. These pulsed field gradient experiments not only facilitate the separation of resonance signals of different components, but also lead to their subsequent identification, and provide information about the number and structure of components in a mixture. Some examples of our initial efforts to establish 1D and 2D PFG‐based NMR experiments for the analysis of mixtures of lubricating oil components are given and assessed to illustrate the potential applications of such techniques in the field of lubricating oils.