In recent years, as the global climate continues to deteriorate, the harm of ultraviolet(UV) radiation to the human body is increasing, but the development of commercial UV-blocking products has not followed the corresponding update. Carbon dots (CDs) are excellent candidates for UV absorbers because of their multi-functional groups, high stability, and low toxicity. In this study, full UV bond absorbing CDs (3A-CDs) were synthesized by a one-step hydrothermal method using anhydrous Citric acid(CA) and 3-aminoquinoline as raw materials. The 3A-CDs have super high UV absorption efficiency, light-aging resistance, and acid and alkaline resistance. Subsequently, different concentrations of 3A-CDs were doped into PVA to prepare 3A-CDs@PVA films with excellent full UV bond absorption and good mechanical properties . Finally, 3A-CDs@PVA films were sandwiched between two pieces of transparent umbrella cloth. The 0.3 wt% 3A-CDs@PVA film with transparent umbrella cloth can achieve a blocking efficiency of more than 97.2% in the full UV bands. Also, SPF is greater than 50, PFA is PA++++, and the visible light transmittance is as high as 93.8%. This study provides a new application and prospect for the development of CDs and their composite products into new, efficient, and durable UV-blocking products.
Ge Ma,Xiaoyong Zhao,Cheng Guo,Shaojia Li,Yaqin Liu,Quan He,Kunsong Chen,Yuanjiang Pan
Current imaging techniques , such as position emission tomography , magnetic resonance imaging and optical imaging , have been developed and applied to imaging acidity in live tissues for years, but they still have some limitations. In the present study, a reliable and interference-free pH imaging method based on matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) was established for the first time. A novel reactive matrix, named glycosyl-3-aminoquinoline (Gly-3AQ), was designed and synthesized here not only to overcome the background interference in the low mass range of MALDI but also provide a new function of acid-responsiveness for the matrix. This matrix was responsive to pH change due to its acid-catalyzed hydrolysis and the hydrolysis product 3-aminoquinoline (3-AQ) has an increase of peak intensity with pH decrease. The Gly-3AQ-based MALDI pH detection method is demonstrated to have good acid-responsiveness in the range of pH 2.0–7.0, and when pH changes 0.5, relative abundance of 3-AQ changes about 1.5 folds. The method showed a very prominent advantage, that is, free-interference when analyzing real samples. Validation for the method revealed pH calibration curve had good linearity (R > 0.9953) with relative standard deviation less than 13.8%. This method was applied to analyze and visualize acidity variation of citrus during development and the changed acidity underwent relative quantitation and statistical analysis. The newly developed reactive matrix has potential application to in-situ MSI of acidity in the biomedical field.
危险品化学品经营许可证（带存储）