ABSTRACT
An ultra-high performance liquid chromatography-mass spectrometry ( UPLC-MS/MS) method was developed for the determination of 8 kinds of cephalosporins, cefoperazone, cefquinome, cefalonium, cefazolin, cefapirin, Ceftiofur, cefpirome and cefalexin, in edible parts of aquatic products. The samples were extracted with acetonitrile-water and cleaned up by multi-walled carbon nanotubes ( MwCNTs) SPE cartridge. All the target compounds were separated on an Acquity Xselect CSH C18 column with gradient elution by using acetonitrile and 0. 1% formic acid aqueous as eluent, and detected by UPLC-MS/MS under ESI+ ionization and MRM mode. Under optimized conditions, this method had a good linearity (R2≥0. 995) and the limits of quantification were in the range of 2-10 μg/kg ( S/N=10 ) . The recoveries of the method for the target compounds spiked at three different levels were 67. 3%-94. 2% with the relative standard deviations (RSDs) of 3. 3%-14%. The method had the characteristics of low cost, high accuracy and good precision, and could meet the requirements of cephalosporins determination.
ABSTRACT
A method was developed for the determination of tetrodotoxin in marine organisms by high perfor-mance liquid chromatography-mass spectrometry with immunoaffinity column. The samples were extracted with 1% acetic acid methanol solution and diluted with phosphate buffer at pH 7-8. After cleaned up by immuno-affinity column, the samples were analyzed by LC-MS/MS and quantitatively determined by external standard method. The chromatographic separation was performed on an ACQUITY UPLC BEH Amide column with gradient elution by using acetonitrile and 5 mol/L ammonium acetate solution containing 0. 1% formic acid as mobile phase. Detection was carried out by electrospray positive ionization mass spectrometry in the multiple reaction monitoring mode. Linear ranges of TTX was in the range of 0. 3 -20. 0 μg/L with correlation coeffi-cient more than 0. 997. The quantification limit of the method was 0. 3 μg/kg. The recoveries of standard addition for tetrodotoxin were 88. 7%-102. 3%, and the relative standard deviation was 2. 0%-6. 4%. The method could be used to identify and quantify tetrodotoxin in marine organisms with satisfactory reproducibility and sensitivity.