Highly sensitive surface plasmon resonance sensor for detection of Methylene Blue and Methylene Orange dyes using NiCo-Layered Double Hydroxide

Surface plasmon resonance (SPR) sensor is a versatile technique to detect toxic materials in the environment. In this study, the SPR technique was used to detect the environmental contaminant dyes such as methylene blue (MB) and methylene orange (MO). The surface of the gold layer was modified using NiCo-layered double hydroxide (LDH) which was fabricated with the electrodeposition method and characterized using field emission scanning electron microscopy, X-ray diffraction spectroscopy, and transmission electron microscopy. The thickness of LDH was controlled by deposition time and a homogeneous coating of LDH was obtained in the short time range of less than 150s. The adsorption of MB and MO on LDH was studied using the SPR technique based on angular modulation. Langmuir adsorption isotherm was fitted for data of adsorbents and the adsorption mechanism was described. The sensor limit and the response time were about 0.005 ppm and 268 s, respectively. It was proved that the sensitivity of the sensor can be controlled by the thickness of the LDH layer. Results indicated that the glass/Au/ NiCo-LDH system is fast and efficient for the detection of the MB and MO dyes in a short time.