Glutathione-functionalized long-period fiber gratings sensor based on surface plasmon resonance for detection of As3+ ions.

Development of simple and accurate methods for the detection of As3+is highly desirable and technically important. In this work, a highly sensitive and selective long-period fiber gratings sensor based on surface plasmon resonance (LPFG-SPR) was developed for As3+detection by designing glutathione-functionalized Au nanoparticles as a signal amplification tag. Based on the chemical interaction between As3+and glutathione, the self-assembling glutathione on the surface of the gold film combines selectively with As3+, and then anchors the glutathione-functionalized Au nanoparticles, which changes the refractive index of the surrounding environment, resulting in a shift of the transmission spectrum. Results show that the sensor could detect As3+with concentrations ranging from 0.02 ppb to 2 ppb. The sensor exhibited excellent specificity for As3+against other metal ions, such as Na+, K+, Fe3+, Mg2+, Cu2+, Pb2+, Ni2+, Ba2+, Ca2+, and Co3+. The fiber sensor was successfully employed to detect As3+in pond water samples, demonstrating that it has the potential for As3+detection with the advantages of low cost, high sensitivity, and a simple structure.