Optical fibre tip sensor coated with chitosan for lead ion detection

In this work, we demonstrate an optical fibre tip sensor coated with chitosan for lead ion (Pb2+) detection. The sensor was fabricated using a tip of standard single mode optical fibre. The fibre tip region was cleaved and dipped into chitosan solution to form a sensitive layer. The coated sensor was exposed to different Pb2+ concentration ranging from 0 to 70 ppm. In order to compare the sensor’s performance, the uncoated optical fibre tip sensor was firstly used to perform the measurement. The chitosan-coated tip sensor has greatly enhanced the sensor’s sensitivity 7 times higher compared to uncoated the sensor with high linearity up to 97%. As the proposed sensor shows a promising potential in detecting Pb2+, we believe the application of the sensor can be extended for environmental and wastewater monitoring.