高效液相色谱法测定水产品中残留的甲氧苄啶

建立测定水产品中残留的甲氧苄啶的高效液相色谱法。样品经三氯甲烷和酸性甲醇溶液提取，提取液调至碱性后用二氯甲烷萃取，萃取液经MCX 柱净化，洗脱液浓缩至近干后用流动相溶解，过微孔滤膜，采用高效液相色谱紫外检测，外标法定量。结果表明，甲氧苄啶在0.05～5.0μg/mL 质量浓度范围内，色谱峰面积与甲氧苄啶质量浓度之间线性关系良好(相关系数为0.999967)，在空白样品的20、40、200μg/kg 3 个加标量条件下，样品平均回收率均大于80%，相对标准偏差小于7%，方法的检测限为20μg/kg。该方法简便快速，基体干扰小，精密度、准确性均能满足水产品中甲氧苄啶的残留分析。

HPLC Determination of Trimethoprim Residue in Aquatic Products

A reversed-phase high performance liquid chromatographic (RP-HPLC) method was developed for the determination of trimethoprim residue in aquatic products. Samples were extracted with a mixture of chloroform, sulfuric acid and methanol (15:14:6, V/V). The resulting extraction solution was alkalized, reextracted with dichloromethane and cleaned up on MCX column. The eluate was pooled, concentrated nearly to dryness, rediluted with the HPLC mobile phase and filtrated through a 0.45 μm pore size membrane. Trimethoprim was detected with an ultraviolet (UV) detector and quantified by external standard method. Good linearity between chromatographic peak area and trimethoprim concentration ranging from 0.05 to 5.0 μg/mL was found (R2 = 0.999967). Average recoveries of trimethoprim in different blank aquatic products spiked at the levels of 20, 40, 200 μg/kg were all more than 80%, with relative standard deviations of less than 7%. The method exhibited a detection limit of 20 μg/kg. Due to the advantages of simplicity, rapidity, little matrix interference and high accuracy and precision, this method is most suitable for the determination of trimethoprim residue in aquatic products.