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.
The qualitative and quantitative research on glycolipids compounds was analyzed by means of the flight time ultra-high performance liquid chromatography tandem mass spectrometry(UPLC-Q-TOF-MS) technology.The mass spectrometry was performed in reflective time-of-flight using electron spraying ionization.The components in monoglycosyldiglycerides(MGDG) and diglycosyldiglycerides(DGDG) were determined in positive ion mode,and the sulfoquinovosyl diacylglycerol(SQDG) were analyzed in negative ion mode.The results showed that each component in golycolipids can be separated effectively with gradient elution in the BEH C18 column.The proportion of each components accounts for total glycolipids can be determined by using degree elution.
