Introduction Aconitine-type alkaloids isolated from the roots of Aconitum carmiechaeli show a potential toxicity and a broad spectrum of bioactivity[1-4].On the basis of the C8-substituent of C19-diterpenoid skeleton,...Introduction Aconitine-type alkaloids isolated from the roots of Aconitum carmiechaeli show a potential toxicity and a broad spectrum of bioactivity[1-4].On the basis of the C8-substituent of C19-diterpenoid skeleton,aconitine-type alkaloids can be divided into diester-diterpenoid alkaloids（DDAs）,monoester-diterpenoid alkaloids（MDAs）,and lipo-alkaloids（Fig.1）.展开更多
The pyrrolizidine alkaloids(PAs) in leaf of Gynura divaricata(L.) DC.was analyzed by LC-MSn technique.The result shows that two hepatotoxic pyrrolizidine alkaloids(HPAs) are detected from the methanol extract of G.div...The pyrrolizidine alkaloids(PAs) in leaf of Gynura divaricata(L.) DC.was analyzed by LC-MSn technique.The result shows that two hepatotoxic pyrrolizidine alkaloids(HPAs) are detected from the methanol extract of G.divaricata leaf,with relative molecular weight of 335 and 365,respectively and lower content.The constituent with relative molecular weight 335 is a retronecine-type alkaloid,and identified as integerrimine;another constituent with relative molecular weight 365 is an otonecine-type alkaloid,speculated to be isomer of usaramine or 18-hydroxyinterrimine.展开更多
A method for simultaneous determination of oxytetracycline,tetracycline,chlortetracycline in animal tissue was successfully established by HPLC-ESI MS/MS.The tetracycline antibiotics in animal tissue were extracted by...A method for simultaneous determination of oxytetracycline,tetracycline,chlortetracycline in animal tissue was successfully established by HPLC-ESI MS/MS.The tetracycline antibiotics in animal tissue were extracted by liquid-solid extraction and cleaned up by SPE.The mass spectrometer was operated in the positive-ion mode using selected reaction monitoring(SRM).The results showed that three tetracycline antibiotics were well separated under the optimal conditions.The detection limits of oxytetracycline,tetracycline and chlortetracycline were 0.16 ng/g,0.1 ng/g and 0.1 ng/g,respectively.The spiked recoveries were range of 84%-94% and the relative standard deviations were 2.4%-2.9%.展开更多
Hydrolysis procedure of N-phosphoryl phenylalanine (DIPP-Phe) was studied by HPLC-ESI-MS/MS. The results showed that (HO)(i-PrO)P(O)Phe was the main intermediate and the hydrolysis of DIPP-Phe also occurred through a ...Hydrolysis procedure of N-phosphoryl phenylalanine (DIPP-Phe) was studied by HPLC-ESI-MS/MS. The results showed that (HO)(i-PrO)P(O)Phe was the main intermediate and the hydrolysis of DIPP-Phe also occurred through a penta-coordinate transition state.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.30472134and30672600)the National Basic Re-search Program of China(No.2006CB5047060).
文摘Introduction Aconitine-type alkaloids isolated from the roots of Aconitum carmiechaeli show a potential toxicity and a broad spectrum of bioactivity[1-4].On the basis of the C8-substituent of C19-diterpenoid skeleton,aconitine-type alkaloids can be divided into diester-diterpenoid alkaloids（DDAs）,monoester-diterpenoid alkaloids（MDAs）,and lipo-alkaloids（Fig.1）.
文摘The pyrrolizidine alkaloids(PAs) in leaf of Gynura divaricata(L.) DC.was analyzed by LC-MSn technique.The result shows that two hepatotoxic pyrrolizidine alkaloids(HPAs) are detected from the methanol extract of G.divaricata leaf,with relative molecular weight of 335 and 365,respectively and lower content.The constituent with relative molecular weight 335 is a retronecine-type alkaloid,and identified as integerrimine;another constituent with relative molecular weight 365 is an otonecine-type alkaloid,speculated to be isomer of usaramine or 18-hydroxyinterrimine.
文摘A method for simultaneous determination of oxytetracycline,tetracycline,chlortetracycline in animal tissue was successfully established by HPLC-ESI MS/MS.The tetracycline antibiotics in animal tissue were extracted by liquid-solid extraction and cleaned up by SPE.The mass spectrometer was operated in the positive-ion mode using selected reaction monitoring(SRM).The results showed that three tetracycline antibiotics were well separated under the optimal conditions.The detection limits of oxytetracycline,tetracycline and chlortetracycline were 0.16 ng/g,0.1 ng/g and 0.1 ng/g,respectively.The spiked recoveries were range of 84%-94% and the relative standard deviations were 2.4%-2.9%.
文摘Hydrolysis procedure of N-phosphoryl phenylalanine (DIPP-Phe) was studied by HPLC-ESI-MS/MS. The results showed that (HO)(i-PrO)P(O)Phe was the main intermediate and the hydrolysis of DIPP-Phe also occurred through a penta-coordinate transition state.
