Microvolume ratiometric fluorescence capillary imprinted array sensor based on bimetallic-nanozyme for rapid intelligent visual detection of five glucocorticoids

Glucocorticoids (GCs), as endocrine disrupting compounds and emerging pollutants, can cause serious harm to human health. Array sensor can provide significant advantages for the simultaneous detection of multiple GCs. However, rapid microvolume identification of multiple GCs in complex environments remains a major challenge. Herein, a microvolume ratiometric fluorescence capillary array sensor (MRFCAS) based on three kinds of bimetallic-nanozyme imprinted materials (Fe/Eu-MOF@MIP(D,R,H)) with good peroxidase-like activity and cross- recognition was developed to rapid accurately distinguish of five GCs (dexamethasone, prednisone, cortisone acetate, betamethasone, hydrocortisone). The MRFCAS was constructed by siphoning imprinted materials in a single capillary tube to produce different response signals and color changes toward five GCs by consuming 18.0 mu L of sample each time. The color changes of MRFCAS converted into digital information were collected by a MATLAB program assisted smartphone to realize real-time detection of five GCs within 7 min. Meanwhile, the principal component analysis was used to deal with fingerprints images and establish a discrete database for accurate identification of five GCs. Remarkably, the MRFCAS has the low detection limit toward five GCs, which were calculated as 1.04 nM, 1.37 nM, 1.23 nM, 1.44 nM and 1.47 nM, respectively. The MRFCAS can identify unknown samples with an accuracy of more than 90.0 %, which provides an alternative method for microvolume detection of multi-targets in complex environments.