title: Bent Fiber Sensor for Preservative Detection in Milk.
abstract: A fiber optic sensor sensitive to refractive index changes of the outer region of the fiber cladding is presented. The sensor uses bent plastic optical fibers in different bending lengths to increase sensitivity. Measurements were made for low-fat milk, the refractive index of which is altered by some preservatives such as formaldehyde, hydrogen peroxide, and sodium carbonate. Concentrations of the preservatives in the milk were changed between 0% and 14.3% while the refractive indices occurred between 1.34550 and 1.35093 for the minimum (0%) and maximum (14.286%) concentrations of sodium carbonate, respectively. Due to bending-induced sensitivity, the sensor is able to detect refractive index changes less of than 0.4%. The results show that there is excellent linearity between the concentration and normalized response of the sensor.
authors.affiliation: Department of Electrical and Electronic Engineering, Erciyes University, Kayseri 38039, Turkey. saracog@erciyes.edu.tr.
authors.forename: Omer Galip
authors.initials: OG
authors.lastname: Saracoglu
authors.affiliation: Department of Electronic and Automation, Kaman Vocational College, Ahi Evran University, Kirsehir 40300, Turkey. sehayber@ahievran.edu.tr.
authors.forename: Sekip Esat
authors.initials: SE
authors.lastname: Hayber
mesh_terms: D000818:Animals; D005336:Fiber Optic Technology / Q000295:instrumentation*; D005520:Food Preservatives / Q000032:analysis*; D008892:Milk / Q000737:chemistry*; D055100:Optical Fibers; D012031:Refractometry
chemical_list: D005520:Food Preservatives
keywords: bent fiber sensor; concentration sensing; milk; plastic optical fiber; refractive index