A sensitive analytical method on cortisol in marine fish serum was established using ultra performance liquid chromatography-quadrupole-time of flight mass spectrometry(UPLC-Q-TOF MS).The cortisol in marine fish serum...A sensitive analytical method on cortisol in marine fish serum was established using ultra performance liquid chromatography-quadrupole-time of flight mass spectrometry(UPLC-Q-TOF MS).The cortisol in marine fish serum was extracted with chloroform,dried under nitrogen gas,and solved in 1:1 methanol-H2O for analysis,with dexamethasone as internal standard.The mass spectrometry was performed in reflective time-of-flight using electron spraying ionization in negative mode,with m/z 407.2 for cortisol and 437.2 for dexamethasone,respectively.The results showed efficient separation of cortisol and dexamethasone are achieved on BEH C18 column.The linearity was good with the equation : Y=0.0154X+0.0451,from 0 to 200 ng/mL,with correlation coefficient of 0.999 3 and low detection limit of 1.64 pg.The average recovery was from 93.3% to 98.1%,with SD less than 10%.Using this method,corsitol in yellow croaker and Japanese sea bass collected in Ningbo China,were determined with content ranged from 0 to 15.81 ng/mL.展开更多
A GC-MS method for the determination of 27 organochlorine pesticides and 15 Pyrethroid pesticides in animal food is established.The method was based on Gel Permeation chromatography combined with solid-phase extractio...A GC-MS method for the determination of 27 organochlorine pesticides and 15 Pyrethroid pesticides in animal food is established.The method was based on Gel Permeation chromatography combined with solid-phase extraction for sample preparation.Rapid qualitative and quantitative analyses was carried out by gas chromatography-mass spectrometry under the selective-ion monitoring mode.The experimental results showed that the correlation coefficients were better than 0.99,the recoveries for spiked standards were 70%-104%,the relative standard deviations were 2.1%-15.9%.展开更多
Due to new emerging fast separation technology and the great demand of high sample throughput in discovery, large number of samples now needed to be analyzed by mass spectrometer with high conformation accuracy.……
N - Linked oligosaccharide were analyzed by using electrospray ionization (ESI) quadrupole time - of- fight mass spectrometry(Q - Tof MS).The isomers showed the same MS and collisioninduced desociation(CID) MS - MS sp...N - Linked oligosaccharide were analyzed by using electrospray ionization (ESI) quadrupole time - of- fight mass spectrometry(Q - Tof MS).The isomers showed the same MS and collisioninduced desociation(CID) MS - MS spectra in the m/z values because the sequence of the sugar residues was the same.But the relative ion abundance of the specific fragment ion was greatly different between the isomers.So, the isomeric oligosacchariedes were distinguished by using the ion abundance in their CID -MS - MS spectra.Discussing the ion abundance in accurate level, quantitative analysis of the mixtures of isomers were also performed.……展开更多
文摘A sensitive analytical method on cortisol in marine fish serum was established using ultra performance liquid chromatography-quadrupole-time of flight mass spectrometry(UPLC-Q-TOF MS).The cortisol in marine fish serum was extracted with chloroform,dried under nitrogen gas,and solved in 1:1 methanol-H2O for analysis,with dexamethasone as internal standard.The mass spectrometry was performed in reflective time-of-flight using electron spraying ionization in negative mode,with m/z 407.2 for cortisol and 437.2 for dexamethasone,respectively.The results showed efficient separation of cortisol and dexamethasone are achieved on BEH C18 column.The linearity was good with the equation : Y=0.0154X+0.0451,from 0 to 200 ng/mL,with correlation coefficient of 0.999 3 and low detection limit of 1.64 pg.The average recovery was from 93.3% to 98.1%,with SD less than 10%.Using this method,corsitol in yellow croaker and Japanese sea bass collected in Ningbo China,were determined with content ranged from 0 to 15.81 ng/mL.
文摘A GC-MS method for the determination of 27 organochlorine pesticides and 15 Pyrethroid pesticides in animal food is established.The method was based on Gel Permeation chromatography combined with solid-phase extraction for sample preparation.Rapid qualitative and quantitative analyses was carried out by gas chromatography-mass spectrometry under the selective-ion monitoring mode.The experimental results showed that the correlation coefficients were better than 0.99,the recoveries for spiked standards were 70%-104%,the relative standard deviations were 2.1%-15.9%.
文摘Due to new emerging fast separation technology and the great demand of high sample throughput in discovery, large number of samples now needed to be analyzed by mass spectrometer with high conformation accuracy.……
文摘N - Linked oligosaccharide were analyzed by using electrospray ionization (ESI) quadrupole time - of- fight mass spectrometry(Q - Tof MS).The isomers showed the same MS and collisioninduced desociation(CID) MS - MS spectra in the m/z values because the sequence of the sugar residues was the same.But the relative ion abundance of the specific fragment ion was greatly different between the isomers.So, the isomeric oligosacchariedes were distinguished by using the ion abundance in their CID -MS - MS spectra.Discussing the ion abundance in accurate level, quantitative analysis of the mixtures of isomers were also performed.……
