在线固相萃取/液相色谱-串联质谱法检测饲料中5种喹噁啉药物残留量

Determination of 5 Quinoxaline Residues in Feed by On-line Solid Phase Extraction / Liquid Chromatography-Tandem Mass Spectrometry Method

建立了在线固相萃取/液相色谱-串联质谱法检测饲料中5种喹噁啉药物的方法。准确称取2 g饲料,用10 m L 0.1%盐酸-甲醇（1∶1）提取,提取液用0.2%甲酸稀释10倍,通过双三元液相色谱采用反相在线固相萃取柱在线富集净化,以0.2%甲酸与乙腈梯度洗脱,同时转移至C18色谱柱上进行分离,串联四极杆质谱检测。实验结果表明,5种喹噁啉药物在50~25 000μg/kg含量范围内线性良好（r〉0.999）;方法的检出限为25μg/kg,定量下限为50μg/kg;方法回收率为72.6%~84.6%,批内和批间相对标准偏差（RSD）均小于10%。本方法较传统固相萃取柱净化法更简捷、经济和稳定。

A high performance liquid chromatography -tandem mass spectrometric method with on- line SPE（ solid phase extraction） was established for the determination of 5 quinoxaline residues in feed. 2 g feed was extracted with 10 mL 0. 1% HCl - CHaOH（ 1 ： 1 ）. The extract was 10 times diluted with 0. 2% formic acid. The dissolution was enriched and purified with a reverse phase on-line SPE column on a double ternary liquid chromatograph. Target compounds were eluted with 0. 2% formic acid and acetonitrile by gradient elution, and separated with an octadecyl silica bonded column. Target compounds were then determined by tandem mass spectrometry. The results showed that the linearities of 5 quinoxalines were good in the range of 50 - 25 000 μg/kg （ r 〉 0. 999 ）. The LOD of the method was 25μg/kg, and LOQ was 50 μg/kg. Recoveries of 5 quinoxalines were in the range of 72. 6% -84. 6% , while RSDs of both in the batch and between the batch were all lower than 10%. The method was proved to be more convenient, economical and stable than the traditional column SPE method.