Detecting mechanism of planar electromagnetic sensor in cooking oil discrimination

The methods of cooking oil discerning are important for the sustainability of the cooking oils supply chain. Classical methods to measure cooking oil quality based on gas chromatography (GC) and high-performance liquid chromatography (HPLC) are too expensive for widespread industrial or household uses and require samples to be analysed in dedicated laboratories thus incurring significant time penalty. Therefore, efforts to develop a reliable and highly sensitive system that may provide on-site cooking oil discrimination is an important priority. Presented research work describes a real time non-invasive discriminating technique for cooking oils. A planar electromagnetic sensor consists of the combination of two sensors which are a meander sensor and an interdigital sensor. The meander type of coil is connected in series with the interdigital coil. Due to the ac voltage applied, the combination of meander and interdigital coils produce electromagnetic field which interacts with the material under test. Three types of cooking oil were prepared namely corn oil, refined palm oil, and sunflower oil. The impedance spectra so obtained showed that the sensor was able to detect the difference between different types of cooking oil samples. Both theory formulation and experiment outcomes were used to testify the measurement for cooking oil discrimination.