Muhammad Bagoes Anargiansyah, Ferdyan Rahmadani Adhi Pramudya, Bilqis Regita Pratiwi Fayensi, Mefina Yulias Rofianingrum, Bambang Widiyatmoko, Muhimmatul Khoiro
A U-shaped Plastic Optical Fiber (POF) sensor coated with chitosan was successfully developed for detecting cadmium (Cd2+) ions in palm oil. While previous optical fiber sensors primarily focused on aqueous media, this study represents an initial investigation into heavy-metal detection in a non-aqueous, viscous medium. The sensor utilizes evanescent-wave absorption to detect refractive index changes caused by Cd2+ binding to the chitosan coating. A 660 nm light source (BF4R) was coupled into the U-shaped POF, and the transmitted signal was converted to voltage readings using a photodetector, an Arduino Nano, and an LCD interface. Palm oil samples with Cd2+ concentrations ranging from 0.05 ppm to 0.20 ppm were tested. The chitosan-coated sensor exhibited improved sensitivity of −7.49 ppm-1 compared to −2.87 ppm-1 for the uncoated fiber, achieving an average accuracy of 95%. This work is an early study of a chitosan-coated POF sensor using palm oil as the medium. Future work will aim to enhance coating uniformity, extend detection range, and explore sol–gel optimization or multiplexed sensing for broader applications in food safety monitoring. © 2025 IAMOT.
Universitas Negeri Surabaya, Ketintang, Surabaya, 60231, Indonesia; National Research and Innovation Agency, Setu, Tangerang Selatan, 15314, Indonesia
