Novel porphyrin covalent organic framework for sensitive fluorescence detection of Cd2+ in tap water and tea beverages

Xiaomin Mai; Kexin Hu; Manning Li; Wannai Lai; Qian Zhou; Yongning Wu; Qinghua He

doi:10.1016/j.foodchem.2025.145310

Novel porphyrin covalent organic framework for sensitive fluorescence detection of Cd²⁺ in tap water and tea beverages

Food Chem. 2025 Jun 23:491:145310. doi: 10.1016/j.foodchem.2025.145310. Online ahead of print.

Authors

Xiaomin Mai¹, Kexin Hu¹, Manning Li¹, Wannai Lai¹, Qian Zhou¹, Yongning Wu², Qinghua He³

Affiliations

¹ Department of Food Science and Engineering, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China.
² Food Safety Research Unit (2019RU014) of Chinese Academy of Medical Science, NHC Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing 100021, China.
³ Department of Food Science and Engineering, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China. Electronic address: qinghua.he@szu.edu.cn.

PMID: 40577906
DOI: 10.1016/j.foodchem.2025.145310

Abstract

Covalent organic frameworks (COFs) have emerged as promising materials for heavy metal detection due to their tunable porosity and structural stability. This study synthesized a novel porphyrin-functionalized COF (COF-PPR) and developed a highly sensitive rapid detection method for Cd²⁺ in tap water and tea beverages based on its fluorescence properties. The COF-PPR exhibited high crystallinity, moderate specific surface area, and excellent chemical/thermal stability. The fluorescence-based Cd²⁺ detection method demonstrated a low detection limit (1.4 μg/L), wide linear range (5-500 μg/L), and good linearity (R² = 0.9958). Through optimization of experimental parameters (solvent, material concentration, pH, storage, and reaction time), the method's sensitivity and accuracy were enhanced. It was successfully applied to detect Cd²⁺ in real samples with recovery rates of 94.6 %-106.0 %, showing satisfactory performance. Mechanistic studies revealed that COF-PPR captures Cd²⁺ through its porphyrin core cavity. This work provides a novel approach for Cd²⁺ detection in food-related matrices and offers a valuable material candidate for food safety applications.

Keywords: Cd(2+); Covalent organic frameworks; Fluorescence detection; Tap water; Tea beverages.