Quantitative Evaluation of Paper Chromatography Spots in Correlation with Physicochemical Properties of Engine Oils

This study explores the potential of paper chromatography for evaluating the condition of used engine oils. A set of 25 oil samples was collected from vehicles operated under real driving conditions and analyzed using both laboratory methods (FTIR spectroscopy, viscosity measurements) and commercial paper test kits. The aim was to quantitatively assess chromatographic spot parameters and investigate their relationships with physicochemical changes in the oil. Refined indicators based on diffusion and contamination zones were proposed and compared with parameters such as oxidation, sulfonation, nitration, and viscosity. The results showed mostly moderate correlations, with only partial consistency between chromatographic and laboratory-derived data. Nevertheless, the analysis highlights that paper chromatography may provide rapid and accessible additional insights for oil condition monitoring, although it cannot substitute standard laboratory testing.