Yuxin Wang, Xueqiang Guo, Chao Zhi, Lifei Yin, Meng Wang, Jinping Li, Libo Li*, Jia Yao*

Cite this article: Chin. J. Struct. Chem., 2025, 44(12), 100729. DOI: 10.1016/j.cjsc.2025.100729

Publication date: December 1, 2025

Keywords: Hydrogen-bonded organic framework; Confined pore space; Ammonia sensing; Turn-on fluorescence; Breath detection

ABSTRACT

The quantitative detection of biological metabolites is a crucial route for early diagnosis of human diseases. Exhaled ammonia (NH3), originating from abnormal metabolism, is normally recognized as the biomarker for liver and kidney lesions. Therefore, developing highly sensitive fluorescent sensing materials is expected to replace the traditional clinical blood tests and facilitate painless diagnosis and telemedicine for patients. However, the weak interaction for ammonia and the small color switching range of fluorescence sensors become the most pressing problem at present. Herein, a porphyrin-based hydrogen-bonded organic framework (HOF-6) with abundant supermolecule interactions in the confined pore space is developed for highly sensitive ammonia detection. The strong interactions between ammonia and the framework greatly promoting the electron rearrangement and enhancing the intensity of fluorescence, HOF-6 successfully achieves trace amounts of ammonia sensing with the limit detection of 0.2 ppm. With the ultrahigh selectivity for ammonia, HOF-6 can accurately determine the amount of ammonia in breath of patients, and the test results are highly consistent with blood ammonia levels. The tailor-made of multiple interactions in the confined pore space provides an effective approach for highly sensitive ammonia detection, as well as brings good news to liver and kidney patients for non-invasive diagnosis and real-time health monitoring.