Simultaneous UHPLC-MS/MS Determination of Gatifloxacin, Moxifloxacin and Levofloxacin in Aquatic Products

A method of UHPLC-MS/MS for simultaneous determination of gatifloxacin, moxifloxacin and levofloxacin in aquatic products was proposed. The samples were extracted with acetonitrile, defatted with n-hexane, and enriched by SPE on Supelclean LC-SCX column. The SPE column was eluted with a mixture of ammonia (aq.) and methanol (25+75), and the eluate obtained was evaporated to dryness by N2-blowing and made up to 2.0 mL with a mixture of acetonitrile and water (10+90). An aliquot of 10 μL was used for UHPLC-MS/MS determination, in which the ACQUITY UPLC BEH C18 column was used as chromatographic column, and mixtures of acetonitrile and 5 mmol·L-1 NH4OAc solution in different ratio were used as mobile phase in gradient elution; positive electrospray ionization as well as multiple reaction monitoring mode were used in the MS detection. Linearity ranges of the compounds were found to be in the ranges within 100 μg·kg-1, with their detection limits (3S/N) in the range of 3.7-4.8 μg·kg-1. Tests for recovery and precision were made by addition of mixed standard solution of the compounds in 3 different concentration levels to 3 samples of aquatic products which were then analyzed by the proposed method. Values of recovery found were in the range of 70.5%-83.7%, and values of RSD′s (n=6) were ≤13%.