Chloramphenicol (CAP), florfenicol (FF), and thiamphenicol (TAP) were
extracted from yellowtail
muscles with ethyl acetate, and the extract was evaporated. The
residues was dissolved with sodium
chloride solution and partitioned with n-hexane to remove
lipids, and then the drugs were extracted
with ethyl acetate. After evaporation of ethyl acetate extract,
the residue was dissolved with
n-hexane followed by ethyl ether and applied to a Sep-Pak
Florisil cartridge successively. The drugs
were eluted from the cartridge with methanol−ethyl ether (3:7), and
eluate was evaporated to
dryness. After acetonitrile and BSA were added to the residues,
the drugs were derivatized at 50
°C for 10 min. After the solvent was evaporated, the residue was
dissolved with ethyl acetate and
applied to gas chromatography−mass spectrometry. The drugs were
separated by a capillary column
coated with 5% phenyl methyl silicone, and SIM was performed at
m/z 208 and 225 for CAP, at
m/z
257 for FF, and at m/z 242, 257, and 330 for TAP.
Recoveries of each drug from yellowtail muscle
fortified at 0.1 ppm were more than 65%, and detection limits were 5
ppb.
Keywords: Chloramphenicol; thiamphenicol; florfenicol; antibacterials;
yellowtail