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

Development of simple and accurate methods for the detection of Asis highly desirable and technically important. In this work, a highly sensitive and selective long-period fiber gratings sensor based on surface plasmon resonance was developed for Asdetection by designing glutathione-functionalized Au nanoparticles as a signal amplification tag. Based on the chemical interaction between Asand glutathione, the self-assembling glutathione on the surface of the gold film combines selectively with As, 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 Aswith concentrations ranging from 0.02 to 2 ppb. The sensor exhibited excellent specificity for Asagainst other metal ions, such as Na, Fe, Mg, Cu, Pb, Ni, Ba, and Co. The fiber sensor was successfully employed to detect Asin pond water samples, demonstrating that it has the potential for Asdetection with the advantages of low cost, high sensitivity, and a simple structure.