Blue-red emission color change from a heavily-doped Eu@MOF composite: Synthesis, characterization and application for 2,4,6-trinitrophenol sensing

Aoyang Yu; Xiaochen Wang; Chengbo Ru

doi:10.1016/j.saa.2023.123263

Blue-red emission color change from a heavily-doped Eu@MOF composite: Synthesis, characterization and application for 2,4,6-trinitrophenol sensing

Spectrochim Acta A Mol Biomol Spectrosc. 2023 Dec 15:303:123263. doi: 10.1016/j.saa.2023.123263. Epub 2023 Aug 15.

Authors

Aoyang Yu¹, Xiaochen Wang², Chengbo Ru³

Affiliations

¹ School of Criminal Science and Technology, Criminal Investigation Police University of China, Shenyang 110035, China; Key Laboratory of Impression Evidence Examination and Identification Technology, Ministry of Public Security, China. Electronic address: yuaoyang39726@163.com.
² School of Criminal Science and Technology, Criminal Investigation Police University of China, Shenyang 110035, China.
³ School of Criminal Science and Technology, Criminal Investigation Police University of China, Shenyang 110035, China; Key Laboratory of Impression Evidence Examination and Identification Technology, Ministry of Public Security, China.

PMID: 37598449
DOI: 10.1016/j.saa.2023.123263

Abstract

2,4,6-trinitrophenol (TPA) natural degradation is nearly impossible and its accumulation threatens ecosystem. Optical sensing is an attractive detection method for TPA with low demand of equipment and data processing, but still needs to be improved. This work was dedicated to increasing probe-loading content so as to improve sensing sensitivity. Three probes derived from Eu(III)-benzimidazole were designed, with their active H atoms replaced by alkyl groups to eliminate the hydrogen bond with supporting host and thus to improve probe-loading content. Their molecular structure, absorption, emission, and excitation spectra were discussed to confirm their sensing potential to TPA. Then these three probes were loaded into host (bio-MOF-1) via ionic exchange method, which was confirmed by XRD, N₂ adsorption/desorption, ICP, and SEM. The loading content and sensing performance of these three probes in bio-MOF-1 were compared. It was found that the elimination of active H atoms indeed increased probe loading content from 44% to 78%, with sensing coefficient increased from 0.010 μM^-1 to 0.029 μM^-1. A ratiometric sensing towards TPA was observed, with blue emission from bio-MOF-1 host increased and red emission from Eu(III) probe decreased, which was detectable by naked eyes. Linear working equations were fitted with high selectivity.

Keywords: 2,4,6-trinitrophenol; Optical sensing; Rare earth doping; Ratiometric sensing.