Tetracyclines constitute one of the most important antibiotic families and represent a classic example of phototoxicity. The photoproducts of tetracyclines and their parent compounds have potentially adverse effects o...Tetracyclines constitute one of the most important antibiotic families and represent a classic example of phototoxicity. The photoproducts of tetracyclines and their parent compounds have potentially adverse effects on natural ecosystem. In this study, the self-sensitized oxidation products of tetracycline （TC） and oxytetracycline （OTC） were determined and the effects of Ca2＋ and Mg2＋on self-sensitized degradation were investigated. The Ca2＋ and Mg2＋ in the natural water sample accounted for enhancement （pH 7.3） and inhibition （pH 9.0） of photodegradation of TC and OTC due to the formation of metal-ions complexes. The formation of Mg2＋ complexes was unfavorable for the photodegradation of the tetracyclines at both pH values. In contrast, the Ca2＋ complexes facilitated the attack of singlet oxygen （102） arising from self-sensitization at pH 7.3 and enhanced TC photodegradation. For the first time, self- sensitized oxidation products of TC and OTC were verified by quenching experiments and detected by LC/ESI-DAD-MS. The products had a nominal mass 14 Da higher than the parent drugs （designated M＋ 14）, which resulted from the 102 attack of the dimethylamino group on the C-4 atom of the tetracyclines. The presence of Ca2＋ and Mg2＋ also affected the generation of M＋ 14 due to the formation of metal-ions complexes with TC and OTC. The findings suggest that the metal-ion complexation has significant impact on the self- sensitized oxidation processes and the photoproducts of tetracyclines.展开更多
LiErF4 was commonly used as a dipolar-coupled antiferromagnet,and was rarely considered as a luminescent material.Herein,we achieved the strong red upconversion emission of LiErF4 simply by an inert shell coating,i.e....LiErF4 was commonly used as a dipolar-coupled antiferromagnet,and was rarely considered as a luminescent material.Herein,we achieved the strong red upconversion emission of LiErF4 simply by an inert shell coating,i.e.,LiErF4@LiYF4.Owing to the unique and intrinsic ladder-like energy levels of Er3+ions,this LiErF4 core–shell nanostructures present red emission(~650 nm)under multi-band excitation in the near-infrared(NIR)region(~808,~980,and^1,530 nm).A brighter and monochromic red emission can be further obtained via doping 0.5%Tm3+into the LiErF4 core,i.e.,LiErF4:0.5%Tm3+@LiYF4.The enriched Er3+ions and strong monochromic red emission natures make LiErF4:0.5%Tm3+@LiYF4 nanocrystals very sensitive for trace water probing in organic solvents with detection limit of 30 ppm in acetonitrile,50 ppm in dimethyl sulfoxide(DMSO),and 58 ppm in N,N-dimethylformamide(DMF)under excitation of 808 nm.Due to their superior chemical and physical stability,these nanoprobes exhibit excellent antijamming ability and recyclability,offering them suitable for real-time and long-term water monitoring.展开更多
基金supported by the National Natural Science Foundation of China (No. 21007018,51078161)the Natural Science Foundation of Hubei Province (No. 2010CDB01104)+1 种基金the Research Fund for the Doctoral Program of Higher Education of China (No. 20100142120004)the 11th Five-year Plan of National Water Environmental Special Program of China (No. 2008ZX07211-10-02)
文摘Tetracyclines constitute one of the most important antibiotic families and represent a classic example of phototoxicity. The photoproducts of tetracyclines and their parent compounds have potentially adverse effects on natural ecosystem. In this study, the self-sensitized oxidation products of tetracycline （TC） and oxytetracycline （OTC） were determined and the effects of Ca2＋ and Mg2＋on self-sensitized degradation were investigated. The Ca2＋ and Mg2＋ in the natural water sample accounted for enhancement （pH 7.3） and inhibition （pH 9.0） of photodegradation of TC and OTC due to the formation of metal-ions complexes. The formation of Mg2＋ complexes was unfavorable for the photodegradation of the tetracyclines at both pH values. In contrast, the Ca2＋ complexes facilitated the attack of singlet oxygen （102） arising from self-sensitization at pH 7.3 and enhanced TC photodegradation. For the first time, self- sensitized oxidation products of TC and OTC were verified by quenching experiments and detected by LC/ESI-DAD-MS. The products had a nominal mass 14 Da higher than the parent drugs （designated M＋ 14）, which resulted from the 102 attack of the dimethylamino group on the C-4 atom of the tetracyclines. The presence of Ca2＋ and Mg2＋ also affected the generation of M＋ 14 due to the formation of metal-ions complexes with TC and OTC. The findings suggest that the metal-ion complexation has significant impact on the self- sensitized oxidation processes and the photoproducts of tetracyclines.
基金the Science and Technology Development Program of Jilin Province(No.20170520162]H)the National Key Research and Development Program of China(No.016YFC0207300)+3 种基金the National Natural Science Foundation of China(Nos.61875191,11874354,61722305,and 61833006)the Program for Jilin University Science and Technology Innovative Research Team(No.JLUSTIRT 2017TD-07)Jilin Development and Reform Commission(No.2018C052-10)the Open Project of State Key Laboratory of Supramolecular Structure and Materials(No.sklssm202023).
文摘LiErF4 was commonly used as a dipolar-coupled antiferromagnet,and was rarely considered as a luminescent material.Herein,we achieved the strong red upconversion emission of LiErF4 simply by an inert shell coating,i.e.,LiErF4@LiYF4.Owing to the unique and intrinsic ladder-like energy levels of Er3+ions,this LiErF4 core–shell nanostructures present red emission(~650 nm)under multi-band excitation in the near-infrared(NIR)region(~808,~980,and^1,530 nm).A brighter and monochromic red emission can be further obtained via doping 0.5%Tm3+into the LiErF4 core,i.e.,LiErF4:0.5%Tm3+@LiYF4.The enriched Er3+ions and strong monochromic red emission natures make LiErF4:0.5%Tm3+@LiYF4 nanocrystals very sensitive for trace water probing in organic solvents with detection limit of 30 ppm in acetonitrile,50 ppm in dimethyl sulfoxide(DMSO),and 58 ppm in N,N-dimethylformamide(DMF)under excitation of 808 nm.Due to their superior chemical and physical stability,these nanoprobes exhibit excellent antijamming ability and recyclability,offering them suitable for real-time and long-term water monitoring.
