Surface plasmon resonance (SPR) sensor for measurement of glucose and ethanol concentrations

Abstract

Surface Plasmon Resonance (SPR) has been extensively applied as a sensor because of its high sensitivity, accurate selectivity, label-free and real-time biomolecular interactions. In this work, simulation and experiment have been studied on the concentration measurement of ethanol and glucose solutions by SPR sensors. The sensor design used a Kretschmann configuration consisting of Glass/Cr/Au and was simulated by using Finite Difference Time Domain (FDTD) method. The ethanol and glucose solutions with varied concentrations were injected into the SPR channel, and the resonance angle was monitored. For the glucose concentration measurement, the resonance angle increases (from 71.607° to 74.434°) as the glucose concentration increases (from 0% to 15%) with a sensitivity of about 111.71/RIU. These experimental results agree with the simulation result, which showed a good linear response for the glucose concentration. However, for the ethanol measurement, an increase in resonance angle to the ethanol concentration is not linear in the higher concentration, which is related to the change in the refractive index. However, the excellent correlation between the experiment and simulation results shows that the SPR sensor has good sensitivity and accuracy.