Shutao Li,Pengyi Ma,Jinping Song,Xiaoting Guo,Jianhua Xue,Qi Ma
It is the first time to report the synthesis of small-molecule passivated boron quantum dots (BQDs) through a bottom-up strategy using L-cysteine (L-Cys) as a passivation agent and ammonium pentaborate tetrahydrate and boric acid as boron sources under a low reaction temperature of 100 °C. The morphology and surface structure of the prepared BQDs were characterized in detail using high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction. The as-obtained BQDs emitted blue fluorescence with a quantum yield of 1.14%, and the particle sizes are mainly distributed between 1.5 nm and 3.5 nm. Stability research results demonstrated that BQDs possess high stability performance. The findings revealed that BQDs could be used as a fluorescence nanoprobe for developing a fluorescence “turn-off/turn-on” sensing platform to detect the drug molecule sulfasalazine (SSZ) and Pb2+. The proposed sensor indicates high sensitivity and selectivity towards SSZ, and the linear response range is 1–100 μmol L−1 with a detection limit of 0.9 μmol L−1. The quenched fluorescence could be recovered by Pb2+ in the range of 40–180 μmol L−1 with a detection limit of 39.7 μmol L−1. The proposed “turn off-turn on” sensor gives satisfactory results for practical sample analysis. Meanwhile, the thermodynamic data were estimated, and the corresponding quenching mechanisms were also discussed in detail. Moreover, BQDs had low cytotoxicity, which presented a potential application in cell imaging. They can also be used in the construction of LED and fluorescent film.
Heavy metal ions impair human health and irreversibly damage the ecosystem. As a result, it is critical to create an efficient approach for identifying heavy metal ions. The electrochemical sensor method is a type of detection method that is highly sensitive, low in cost, and allows for real-time monitoring. In this study, solid carbon spheres were made using resorcinol and formaldehyde as raw materials, followed by the formation of PEDOT/carbon sphere composites via in situ oxidative polymerization, and Pb2+was detected utilizing them as electrode modification materials. The structure of the PEDOT/carbon spherical composites was analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). To investigate the electrochemical properties of these composites, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV) were employed. In addition, the detection mechanism of the material for Pb2⁺ was studied using CV. The PEDOT/carbon sphere sensor showcased an extensive linear detection range of 7.5 × 10−2to 1.0 μM for Pb2+ions, achieving a low limit of detection (LOD) of 3.5 × 10−2nM and displaying exceptional selectivity. These results can be attributed to its large surface area, superior electrical conductivity, and outstanding electron transport properties. This study offers an effective material for detecting low concentrations of Pb2+, with potential applications in future Pb2+detection.
危险品化学品经营许可证（带存储）