Pyrogallol Detection Based on the Cobalt Metal–Organic Framework of Nanomaterial-Enhanced Chemiluminescence

Abstract

The cobalt metal–organic framework (Co-MOF) is a kind of crystalline porous material within a periodic network structure, which is formed via the self-assembly of a Co metal center and a bridged organic ligand. In this paper, a Co-MOF was facilely synthesized via an ultrasonic method and applied to enhance the chemiluminescence (CL) emission of the NaIO4-H2O2 system. The synthesized Co-MOF was nanosheet-like in nature and stacked in 2–3-micrometer flower shapes. Compared to the NaIO4-H2O2 system without a Co-MOF, the CL intensity of the Co-MOF-NaIO4-H2O2 system was enhanced about 70 times. This CL mechanism was determined to be a result of the synergistic effects of chemiluminescence resonance energy transfer (CRET) and electron–hole annihilation (EHA). The Co-MOF not only acted as a catalyst to accelerate the generation of reactive oxygen species in the CL reaction, but also worked as an emitter to further enhance the CL. Based on the Co-MOF-NaIO4-H2O2 system, a highly sensitive CL analysis method was established for pyrogallol (PG) detection. Addition of PG into the CL system generated 1O2*, which could transfer energy to the Co-MOF and further enhance the CL response. The enhanced CL was linear with the PG concentration. The CL analysis method exhibited a linear range of 1 × 10−4 M to 1 × 10−7 M, as well as having a linear correlation coefficient of 0.9995 and a limit of detection of (S/N = 3) of 34 nM.