Simultaneous determination of tetracyclines, fluoroquinolones, and sulfonamides in chicken manure using solid-phase extraction and high performance liquid chromatography

A highly efficient and economic method for the simultaneous determination of six common antibiotics (two tetracyclines, two quinolones, and two sulfonamides) in chicken manure was developed by using solid. phase extraction and high performance liquid chromatography (SPE-HPLC). The samples were extracted by using a mixture of the EDTA-McIlvaine buffer and a mixed organic extractant (methanol. acetonitrile. acetone, 2:2:1, v/v/v), cleaned by a hydrophile. lipophile balance (HLB) cartridge, eluted by methanol. dichloromethane (7:3, v/v), and separated by HPLC with an acetonitrile. 0.7% (v/v) H3PO4 aqueous solution as the mobile phase. The detection wavelength and temperature of the chromatographic column were 270 nm and 32 degrees C, respectively. All antibiotics showed great linear relationships in the range of 0.5-100 mg/L; the correlation coefficients (r(2)) of the standard curves were between 0.999 9 and 1; the recoveries of antibiotics were between 70.0% and 116.3%; and the relative standard deviations were between 1.2% and 16.6%. The limits of detection were 1.3-6.7 mu g/kg; and the limits of quantity were 3.5-9.2 mu g/kg. This method was used to detect antibiotics in chicken manure from a hennery in Fushun, Liaoning Province. The contents of norfloxacin and enrofloxacin (quinolones) were from not detected to 9.23 mg/kg and 1.57-7.69 mg/kg, respectively, that of sulfamethazine (sulfonamides) were 2.02 - 13.05 mg/kg, while sulfamethoxazole, oxytetracycline, and tetracycline were undetectable.