A Fiber-Optic Electrochemilunescence Sensor Placed into Sample Solution

Abstract: A novel fiber-optic electrochemiluninescence sensor has been developed. It can be conveniently applied by placing into the sample solution in a manner similar to a conventional ion selective electrode, without requiring liquid luminous reagent and a flowing system. The sensor is consisted of an independent probe and a case for exclusion the ambient light, allowing the sample solution to pass through. Within the body of the probe, an optical fiber is utilized to collect and transmit light signal. In the three electrode configuration of the probe, a Pt electrode coated with Ru(bpy)₃²⁺- modified chitosan/silica gel membrane is used to give the electrolytic potential and provide a selective luminous membrane. The linear responses of the sensor to oxalic acid and amino acid were obtained in the concentration range of 2.0 × 10^-4 to 1.0 × 10 ^–2 mol/dm³ with the relative standard deviations of 3.5% and 5.7%, respectively. The response of the sensor was not less than 80% of the initial value after the service time was over one month.