Dissolved organic matter （DOM） has been identified as precursor for disinfection by-products （DBPs） formation during chlorination. Recently, it has been demonstrated that the characteristics of DOM influence the D...Dissolved organic matter （DOM） has been identified as precursor for disinfection by-products （DBPs） formation during chlorination. Recently, it has been demonstrated that the characteristics of DOM influence the DBPs formation mechanism. A study was, therefore, initiated to investigate the effects of DOM fractions on DBPs formation mechanism. In the chlorination process, organic acids are dominant precursors of total thihalomethanes （TTHM） because of the vc-o and unsaturated structures. Furthermore, the TTHM formation of organic acids was affected by pH more greatly. Based on the fluorescence spectroscopy analysis, DOM fractions contained several fluorescence substances. During chlorination, humic acid-like substances were found to exhibit high chlorine reactivity and hydrophobic organics decomposed to smaller molecules faster than hydrophilic organics even at lower chlorine dosages. Unlike hydrophobic fractions, hydrophilic organics showed no toxicity following chlorination, suggesting that the toxic structures in hydrophihc organics showed high chlorine reactivity during chlorination.展开更多
A novel fluorescence probe for the detection of Cu2+ has been designed and synthesized, which is based on a ring-opening reaction of spirolactam triggered by Cu2+ . This probe exhibits excellent Cu2+ ion selectivity a...A novel fluorescence probe for the detection of Cu2+ has been designed and synthesized, which is based on a ring-opening reaction of spirolactam triggered by Cu2+ . This probe exhibits excellent Cu2+ ion selectivity as well as significant color changes visible to the naked eye at the concentration of 0.03 mM (ca. 2.0 mg/L), the WHO (World Health Organization) recommended level (2.0 mg/L) of Cu2+ ions in drinking water. This novel rhodamine-based fluorescence probe can be directly used to detect Cu2+ with satisfactory sensitivity and selectivity in aqueous solution.展开更多
Solamargine, （25R）-3β-（O-a-L-rhamnopyranosyl-（1--2）-[O-a-L-rhamnopyranosyl-（1--4）]-β-D-glucopyranosloxy}-22a-N- spirosol-5-ene, isolated from the berries of solanum aculeastrum, has been synthesized in 26.8% ...Solamargine, （25R）-3β-（O-a-L-rhamnopyranosyl-（1--2）-[O-a-L-rhamnopyranosyl-（1--4）]-β-D-glucopyranosloxy}-22a-N- spirosol-5-ene, isolated from the berries of solanum aculeastrum, has been synthesized in 26.8% overall yield. First glycosylation before N-cyclization significantly facilitated synthesis of the desired molecule. We anticipate that this work will provide a new approach to access solamargine and its diversified analogues.展开更多
基金supported by the National Natural Science Foundation of China (No. 50538090)the Funds for Creative Research Groups of China (No. 50621804)the High-Tech Research and Development Program (863) of China (No. 2007AA06Z338).
文摘Dissolved organic matter （DOM） has been identified as precursor for disinfection by-products （DBPs） formation during chlorination. Recently, it has been demonstrated that the characteristics of DOM influence the DBPs formation mechanism. A study was, therefore, initiated to investigate the effects of DOM fractions on DBPs formation mechanism. In the chlorination process, organic acids are dominant precursors of total thihalomethanes （TTHM） because of the vc-o and unsaturated structures. Furthermore, the TTHM formation of organic acids was affected by pH more greatly. Based on the fluorescence spectroscopy analysis, DOM fractions contained several fluorescence substances. During chlorination, humic acid-like substances were found to exhibit high chlorine reactivity and hydrophobic organics decomposed to smaller molecules faster than hydrophilic organics even at lower chlorine dosages. Unlike hydrophobic fractions, hydrophilic organics showed no toxicity following chlorination, suggesting that the toxic structures in hydrophihc organics showed high chlorine reactivity during chlorination.
基金supported in partial by the National Natural Science Foundation of China (20921063 & 20877090)the National High Technology Research and Development Program (863 Program, 2007AA06A407)
文摘A novel fluorescence probe for the detection of Cu2+ has been designed and synthesized, which is based on a ring-opening reaction of spirolactam triggered by Cu2+ . This probe exhibits excellent Cu2+ ion selectivity as well as significant color changes visible to the naked eye at the concentration of 0.03 mM (ca. 2.0 mg/L), the WHO (World Health Organization) recommended level (2.0 mg/L) of Cu2+ ions in drinking water. This novel rhodamine-based fluorescence probe can be directly used to detect Cu2+ with satisfactory sensitivity and selectivity in aqueous solution.
基金supported partially by the National Basic Research Program of China (2011CB936001)National Natural Science Foundation of China (20732001,20872172,21072217)
文摘Solamargine, （25R）-3β-（O-a-L-rhamnopyranosyl-（1--2）-[O-a-L-rhamnopyranosyl-（1--4）]-β-D-glucopyranosloxy}-22a-N- spirosol-5-ene, isolated from the berries of solanum aculeastrum, has been synthesized in 26.8% overall yield. First glycosylation before N-cyclization significantly facilitated synthesis of the desired molecule. We anticipate that this work will provide a new approach to access solamargine and its diversified analogues.
