Impedimetric sensor for cooking oil discernment based on planar electromagnetic sensor array

Abstract

This paper presents an investigation of the use of an impedimetric sensor which can be used to distinguish several types of cooking oils for three types of conditions such as characterization, adulteration, and the amount of usage for deep-frying conditions, utilizing the parallel configured planar electromagnetic sensor array with electrochemical impedance spectroscopy (EIS) technique. The planar electromagnetic sensor was designed by combining two types of sensors which are an interdigital sensor and a meander sensor as the interface to interact with the test samples. The meander type of coil was connected in series with the interdigital sensor coil. Several types of commercial cooking oil samples were prepared. However, since commercial palm oil is commonly used by Malaysian consumers, focus is on its samples preparation for adulteration and usage conditions. The results obtained showed that the sensor was able to differentiate the samples based on the impedance spectra in the range of frequencies from 100 Hz to 5 MHz. The equivalent circuit for the planar electromagnetic sensor was determined, and the equivalent parameter units were estimated with an estimation error of less than 8%. The conductivity and relative permittivity for the cooking oil samples were calculated, and a corrective factor was used to reduce the sensor measurement error. The reliability and repeatability of the planar electromagnetic sensor was also presented in this paper.