Highly sensitive fluorescent probe for selective detection of hypochlorite ions using nitrogen-fluorine co-doped carbon nanodots

Dual-emissive carbonized polymer dots for the ratiometric fluorescence imaging of singlet oxygen in living cells

Singlet oxygen (¹O₂) is a type of reactive oxygen species (ROS), playing a vital role in the physiological and pathophysiological processes. Specific probes for monitoring intracellular ¹O₂ still remain challenging. In this study, we develop a ratiometric fluorescent probe for the real-time intracellular detection of ¹O₂ using o-phenylenediamine-derived carbonized polymer dots (o-PD CPDs). The o-PD CPDs possessing dual-excitation-emission properties (blue and yellow fluorescence) were successfully synthesized in a two-phase system (water/acetonitrile) using an ionic liquid tetrabutylammonium hexafluorophosphate as a supporting electrolyte through the electrolysis of o-PD. The o-PD CPDs can act as a photosensitizer to produce ¹O₂ upon white LED irradiation, in turn, the generated ¹O₂ selectively quenches the yellow emission of the o-PD CPDs. This quenching behavior is ascribed to the specific cycloaddition reaction between ¹O₂ and alkene groups in the polymer scaffolds on o-PD CPDs. The interior carbon core can be a reliable internal standard since its blue fluorescence intensity remains unchanged in the presence of ¹O₂. The ratiometric response of o-PD CPDs is selective toward ¹O₂ against other ROS species. The developed o-PD CPDs have been successfully applied to monitor the ¹O₂ level in the intracellular environment. Furthermore, in the inflammatory neutrophil cell model, o-PD CPDs can also detect the ¹O₂ and other ROS species such as hypochlorous acid after phorbol 12-myristate 13-acetate (PMA)-induced inflammation. Through the dual-channel fluorescence imaging, the ratiometric response of o-PD CPDs shows great potential for detecting endogenous and stimulating ¹O₂in vivo.

Rapid determination of illegally added Sudan I in cake by triphenylamine functionalized polyhedral oligomeric silsesquioxane fluorescence sensor

Triphenylamine functionalized polyhedral oligomeric silsesquioxane (POSS@TPA) was prepared using the Friedel-Crafts reaction with tris(4-bromophenyl)amine (TPA) as the functional monomer and polyhedral oligomeric silsesquioxane (POSS) as the framework. The as-prepared POSS@TPA has a stable structure and accomplished pore performance, allowing for the selective adsorption of Sudan I and result in the fluorescence quenches of POSS@TPA. Thus, the POSS@TPA could be used as sensors to fluorescence detect 0.12-7.4 mg/L Sudan I, with a detection limit of 0.091 mg/L. Moreover, the POSS@TPA have good reuseability can be reused more than 5 cycles after washing. Noteworthily, the response time of POSS@TPA for determination was as short as 1 min. Furthermore, the sensor was effectively used to determine Sudan I in cakes with excellent recoveries (86.4-108.8 %) and relative standard deviations (2.5-4.9 %). The results matched those of high-performance liquid chromatography (HPLC). Our work shows great potential in terms of the rapid detection of food safety.

Aldehyde Spiropyran Fluorescent Probe for Rapid Determination of Hydrazine in Environmental Water

Hydrazine often receives publicity because it has a wide range of applications but high toxicity at the same time. Herein, we invented a novel aldehyde spiropyran fluorescent probe (SP-CHO) for fluorescent determination of hydrazine. The probe was synthesized through a hydralysis reaction and a condensation reaction. It exhibits specific response to hydrazine. The influence factors and anti-interference ability of SP-CHO identifying hydrazine were studied. HRMS, ¹ H NMR and DFT calculations were used to reveal the recognition mechanism. Results showed that SP-CHO can be used for fluorescent determination of hydrazine with high selectivity and sensitivity. An SP-CHO-based fluorescent method was established for quantitation of hydrazine. The detection limit was 1.26 μmol/L, and the linear range is 5-100 μmol/L. The determination of hydrazine in water samples can be completed within 10 minutes, which shows good application prospects in real-time detection and process monitoring.