Fiber optic luminescence-based sensor using metal-organic frameworks for detection of rare earth elements

A method to detect and quantify rare earth elements in a fluid contacting a sensor, comprising:

• providing the sensor to an environment such that the sensor is in contact with the fluid, wherein the sensor comprises a fiber extending between a first end and a second end along a longitudinal axis, wherein the sensor further comprises a coating on the second end of the fiber, wherein the coating comprises a metal-organic framework material;
• removing the sensor from contact with the fluid and drying the sensor;
• interrogating the sensor with light;
• collecting a luminescent signal;
• and
• detecting the rare earth elements in the fluid contacting the sensor using the luminescent signal, wherein the fluid comprises a pH less than or equal to about 1, a concentration of non-rare earth element metals at least several orders of magnitude greater than a concentration of rare earth elements therein, or combinations thereof.