A dual-emission fluorescence probe for simultaneous quantification of CN− and Cr2O72− ions based on modified g-C3N4

Abstract

In this work, the optical applications of g-C3N4 modified with Hg2+ as a fluorescence sensor for quantification of two toxic anions (CN− and Cr2O72−) were studied. The prepared nanostructures were characterized with XRD, FTIR, TEM and luminescence techniques. TEM image revealed that the size of nanostructures is smaller than the 60 nm. Investigation of fluorescence emission showed that the modified g-C3N4 has two distinct emission spectra centered at 368 and 450 nm. The ability and feasibility use of these emission peaks as sensitive signals for CN− and Cr2O72− ions were investigated. The obtained results illustrated that the fluorescence intensity at 368 nm was sensitive toward CN−. In addition, the second emission peak at 450 nm efficiently quenched in the presence of Cr2O72−. According to the titration experiments, the detection limit for CN− and Cr2O72− were calculated as 1.5 μM and 18 nM, respectively. The competitive test showed that the sensor has an excellent affinity toward these anions over the other anions and species. The sensor can be proposed a dual fluorescence emission probe for simultaneous detection and determination of CN− and Cr2O72− without any negative interaction effect. The applicability of the proposed sensor was checked by determination of Cr2O72− in real samples such as milk was investigated.