A novel cobalt-based metal-organic framework catalyst for enhanced luminol chemiluminescence and choline detection

A novel Co-based MOF (Co 2 DDA), was successfully synthesized. • Co 2 DDA enhanced luminol–H 2 O 2 chemiluminescence by about 6000-fold. • Co 2 DDA catalyzed H 2 O 2 to generate 1 O 2 , .•OH and O 2 •− under alkaline conditions. • A cascade catalytic CL platform based on ChOx and Co 2 DDA was developed for choline sensing. • Choline was detected from 5 to 150 μM with an LOD of 4.21 μM. A cobalt-based metal-organic framework (Co 2 DDA, DDA = 1,5-diamino-4,8-dihydroxy-9,10-anthracenedione) was synthesized in this study. Under the catalysis of Co 2 DDA, the chemiluminescence (CL) intensity of the luminol–H 2 O 2 system increased by approximately 6000-fold. The catalytic mechanism of Co 2 DDA was elucidated through CL spectrum, UV–vis absorption spectroscopy, radical scavenger experiments, and electron spin resonance (ESR) spectroscopy. The results demonstrated that Co 2 DDA exhibited excellent catalytic activity, facilitating the decomposition of H 2 O 2 under alkaline conditions and enhancing the production of reactive oxygen species (ROS), including 1 O 2 , •OH, and O 2 •− . These ROS rapidly react with luminol to produce the excited-state oxidation product 3-aminophthalate anion (3-APA*), which emits strong CL at 440 nm when transitioning to the ground state. Under the cascade catalysis of choline oxidase (ChOx) and Co 2 DDA, the system exhibited a remarkable response toward choline. Based on this finding, a sensitive CL method for the detection of choline was developed. Under optimized conditions, the proposed CL system showed a good linear relationship in the concentration range of 5–150 μM, with a detection limit as low as 4.21 μM (3 σ /K). Significantly, this strategy can be further extended to the detection of other biomolecules that generate H 2 O 2 as a reaction product. Download: Download high-res image (299KB) Download: Download full-size image