Examination of adulteration of edible oils at the wavelength of 660nm using a u–shaped sensing element based extrinsic fiber optic sensor

Abstract

Edible oils such as groundnut oil and coconut oil etc, play a vital role in a consumer applications. These oils are used as compulsory ingredient in almost all culinary items large scale in the major part of the world. Therefore the study of purity of these oils becomes essential in order to maintain good health and hygiene of the consumers across the world. A novel approach has been adopted to develop an advanced fiber optic sensor to study the adulteration of coconut and groundnut oils more accurately by using U–shaped glass element based extrinsic fiber optic sensor in the present work. A U–shaped glass rod having specific geometrical parameters is used as an extrinsic sensing probe, which is connected in between a source operating at the wavelength of 660nm and an optical power detector by using two PCS fibers of 200/230µm. For the study of adulteration of edible oils two cheap oils i.e., paraffin oil and palm oil have been selected and mixed at different ratios and are introduced into the sensing region one after the other. A gradual decrease in the optical output power has been observed in the output detector, when the mixtures with increased cheap oil introduced around the sensing element. Thus, a relationship can be formed between the powers observed at output to the amount of cheap oil mixed in pure oils. Calibrated curve can be drawn between power reaching at the output end of the sensor and refractive index of the mixtures of pure oils adulterated with cheap oils, which can be used to measure the unknown amount of cheap oil in pure edible oil at room temperature accuracy of 10–5.