An ultra high performance liquid chromatographic(UPLC) method was established for the rapid determination of sulfamethoxazole(SMZ)

N acetyl sulfamethoxazole(N-ac-SMZ) and trimethoprim(TMP) in fish tissues

including muscle and skin in natural proportions

liver

kidney

gill and plasma.Samples of muscle and skin in natural proportions

liver

kidney and gill tissues of fish were prepared using the modified QuEChERS

and plasma sample was prepared by a liquid-liquid extraction procedure.The analytes were separated on an Acquity UPLC-BEH C18 column(2.1 mm×100 mm，1.7 μm) with methanol and water containing 0.1%acetic acid as mobile phases

at a detection wavelength of 270 nm

using an absorbent minus median baseline filter(MBF) in data acquisition mode.The external standard method was used for quantitation.Results showed that there were good linear relationships for SMZ

N ac-SMZ and TMP in the range of 0.05-10 mg/L with correlation coefficients(r2) not less than 0.998 9.The detection limits and quantitation limits for the analytes in fish tissues were 25 μg/kg and 50 μg/kg

respectively.Recoveries for the target compounds at spiked levels of 0.05-2.00 mg/kg were between 68.2%and 97.3%with relative standard deviations of 1.7%-13%.The method is simple

accurate and highly sensitive

and is suitable for the residue determination

pharmacokinetic and tissue distribution study of SMZ

N-ac-SMZ and TMP in fish.