Development of a MOF Based Potentiometric Sensor for Determination of Rhodamine B

Rhodamine B is a basic, red and cationic dye belonging to the class of xanthene dyes. Rhodamine B is harmful to human and animal health when taken orally or in contact with skin. It causes irritation to the skin, eyes and respiratory tract. It has been shown experimentally to be carcinogenic, reproductive and developmental toxicity, neurotoxicity, and chronic toxicity to humans and animals. Because of its intense color and availability, Rhodamine B has been illegally added to food products, particularly paprika seasonings, to enhance the natural color. In this study, a Rhodamine B-selective potentiometric sensor was developed by using MIL-53 (Al) as ionophore in the prepared membrane composition. The sensor prepared with 6% MIL-53 (Al), 26% PVC, 68% DOS membrane composition exhibited the best potentiometric performance. The Rhodamine B-selective sensor exhibited a linear response in the concentration range of 1.0×10−6 M-1.0×10−2 M with a slope of 58 mV/decade and a detection limit of 5.0×10−7 M. The response time of the Rhodamine B-selective sensor was less than 5 seconds and it was not affected by hydronium ion in the pH range of 4.49-8.08. Analytical application of the sensor was successfully carried out in Van Lake, waste water and tap water.