Reusable surface plasmon resonance sensor for rapid detection of Cu2+ based on modified-chitosan thin film as an active layer

In this article, a reusable surface plasmon resonance (SPR) sensor for rapid detection of copper ions (Cu2+), based on optimized silver/gold (Ag/Au) composite film modified by modified-chitosan (MCS) thin film as an active layer, was achieved. We employed a four-layer Kretchmann semi-cylindrical prism configuration and induced a reference beam into the experimental system to improve the sensitivity and stability, and investigated the cross-linking technique of CS solution, the spin coating process of MCS film, the stability of active layer, the rebirth power of SPR sensor, and the detection for trace Cu2+. The rate of swelling or dissolution of MCS film after flushing sensor chip for four times is less than 9 x 10(-4)/min, and the decline of signal value is less than 1.5% after MCS film adsorbing Cu+2 and multiple flushing. The elution and capacity rates are above 96% after five times of elution for the sensor by EDTA solution with 0.5mmol/L. Within 1-5ppm, the SPR sensor was found to possess sensitivity of 0.7271ppm(-1). The LOD is 18ppb for the trace Cu2+. The present SPR sensor not only could be used in trace monitoring of Cu2+ but also could be extended to other potential applications. (C) 2018 Elsevier B.V. All rights reserved.