Development of an Eu3+ Functionalized Metal-Organic Framework-based Nanofibrous Sensor for Biomedical Monitoring of Hippuric Acid in Urine Samples

The current study focuses on the development of a rapid and cost-effective photoluminescence sensor for quantifying hippuric acid (HA) in human urine. This sensor utilizes Eu3+-functionalized metal-organic framework (MOF) embedded in polyacrylonitrile (PAN) nanofibers. The electrospinning technique was employed to enhance the stability and performance of the Eu3+@Cu-BTC embedded PAN nanofibers.The prepared sensor demonstrated acceptable selectivity and sensitivity, exhibiting a linear relationship between the logarithm of HA concentration (Lg [HA]) and the response of both the powder and nanofiber sensors, with R² values of 0.993 and 0.991, respectively. Furthermore, the limit of detection (LOD) was determined to be 3.7 μg/mL for the powder sensor and 1.2 μg/mL for the nanofiber sensor, both significantly below the American Conference of Governmental and Industrial Hygienists (ACGIH) Biological Exposure Index (BEI) for HA, which is set at 2 mg/mL.This research highlights the advantages of electrospinning-based sensors using MOFs, including reusability, reduced measurement errors, user-friendliness, and simplified sample preparation. These features underscore their potential for rapid biological monitoring of toluene exposure in occupational settings.