A fluorescent sensor based on UiO-66-NH₂@CdTe QDs for sensitive detection of pentachlorophenol in tobacco paper

Pentachlorophenol is highly toxic and carcinogenic, and now its use is strictly prohibited. However, there remains a risk of residual contamination in paper products, which makes the development of highly sensitive detection methods crucial for safeguarding public health. In this study, cadmium telluride quantum dots (CdTe QDs) with tunable emission wavelengths were used as fluorescent materials. In order to avoid interference from the background fluorescence of tobacco paper on the detection process, they were combined with the highly adsorbent UiO-66-NH₂ to address the limitation of insufficient adsorption and enrichment capacity in single quantum dots, thereby constructing a highly sensitive nanocomposite fluorescent probe for the detection of pentachlorophenol in tobacco paper. In the analysis of tobacco paper extracts, pentachlorophenol is first adsorbed and concentrated by UiO-66-NH₂, and subsequently interacts with UiO-66-NH₂@CdTe QDs through hydrogen bonding. Ultimately, the fluorescence intensity of the system decreases significantly due to a dynamic quenching mechanism, thereby enabling the detection of the target compound. The response time is only 3 min. In the range of 0.01-1 µM, pentachlorophenol concentration displayed a linear correlation with the fluorescence intensity, and the limit of detection was 0.00675 µM. The method exhibits recovery rates of 98.7-101.4% and a relative standard deviation ≤ 8.3%. Its high sensitivity and rapid detection make it suitable for the rapid screening and quality control of pentachlorophenol residues in tobacco paper.