Dielectric spectroscopy of liquids through a combined approach: evaluation of the metrological performance and feasibility study on vegetable oils

In this work, a time domain-based approach for the estimation of the dielectric parameters of liquids is presented. The proposed approach combines traditional time-domain reflectometry measurements with a specific data processing and modeling that leads to the evaluation of the Cole-Cole parameters. The pivotal step of the procedure is the implementation of an accurate transmission line model of the used measurement cell. In this way, the error contributions due to undesired parasitic effects are minimized; hence, the overall accuracy is significantly enhanced. The proposed approach is tested through repeated measurements on well-referenced materials; this also allowed performing the related metrological analysis. Successively, the proposed procedure is applied for the evaluation of the Cole-Cole parameters of vegetable oils. In fact, at the state-of-the-art, only limited data are available for the dielectric characteristics of vegetable oils. In particular, ten different types of vegetable oils are considered. Results show that the proposed approach has strong potential also for possible practical applications in the area of anti-adulteration and quality control.