Combined NMR methods in quality control of lubricants in green energy production.

NMR methods were applied for lubricant analysis. Different factors influence real aging of lubricants on diverse length scales and are captured by NMR. Chemical conversion of additives is addressed by NMR spectroscopy. High-field NMR experiments allow identification and quantification of chemical components and are transferred to benchtop devices. Molecular dynamics and contaminations like fuel or abrasion are addressed via NMR relaxation and diffusion. Quality parameters were extracted via suitable data analysis of NMR raw data which allow the detection of aging and indicate changes in the oil composition. At the same time the methodology is optimized to the conditions in quality control. The feasibility is shown on the example of series of lubricants from applications in regenerative energy production, namely wind turbine oils and bio gas motor oils.