有机肥中4类典型兽药抗生素的多残留测定

建立了固相萃取-超高效液相色谱-串联质谱（SPE—UPLC—MS／MS）法同时测定有机肥中7种磺胺类、4种氟喹诺酮类、4种四环素类和3种大环内酯类抗生素残留的方法。采用乙腈和磷酸盐缓冲液（pH=3）的混合液作为有机肥样品的提取溶液，用强阴离子交换柱（SAX）-亲水亲脂平衡萃取柱（HLB）串联进行提取液的富集和纯化。以甲醇-φ=0．1％的甲酸溶液作为流动相，进行液相质谱分析。18种抗生素在5—500μg·kg-1的浓度范围内线性关系良好，决定系数（r2）1〉0．99。以3倍信噪比估算磺胺类、氟喹诺酮类、四环素类和大环内酯类的检测限分别为0．37～4．65、0．43—2．42、0．94～2．78和0．83～4．20μg·kg-1，这4类抗生素50和500μg·kg。2个添加水平的样品平均加标回收率分别为71．6％～94．3％、72．3％～86．7％、71．0％～102．2％和70．7％～93．3％，相对标准偏差在2．1％～11．4％之间。采用所建方法对南京地区市售8种有机肥中18种抗生素含量的测定结果显示，除磺胺类外，其他抗生素均有不同程度的检出。

Simultaneous Determination of Residues of Four Typical Categories of Veterinary Antibiotics in Organic Fertiliz- ers.

A new method using SPE - UPLC - MS/MS was developed to detetnine residues of four typical categories of veterinary antibiotics in organic manure. The method uses the solution composed of aeetonitrile and phosphate buffer （ pH = 3 ） for extraction of organic manure samples, and the series of SAX and HLB to purify and enrich the extract. Methanol -φ = 0. 1% formic acid was chosen as carrier for liquid chromatographic analysis. When the concentrations of the 18 antibiotics were in the range of 5 - 500 μg·kg-1 , they showed good linear relationships, with determination coefficients （ r2 ） ≥ 0. 99. When the mass concentration of the antibiotics was raised to the range of 50 - 500μg·kg-1 , the recovery rates of sulfonamides, fluoroquinoloncs, tetracyclincs and macrolides varied in the range from 71.6% to 94. 3% , from 72. 3% to 86. 7% ,from 71.0% to 102. 2% and from 70. 7% to 93.3% , respectively, with relative standard deviation va- rying in the range of 2. 1% to 11.4%. This method was applied to determine residues of veterinary antibiotics in organic fertilizers on sale in Nanjing. In addition to sulfonamides, others were also detected to a varying extent.