Abstract: A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was established for the determination of nonylphenol in milk powder. Samples were extracted with acetonitrile and cleaned up with a solid phase extraction column. The analytes were separated on a Waters ACQUITY UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm), detected by electrospray ionization in the multiple reaction monitoring (MRM) mode, and quantified by an external standard method. The results showed that good linearity was observed in the concentration range of 1–200 ng/mL (R2 > 0.99). The limit of detection（LOD, RS/N = 3）was 2 μg/kg and the limit of quantitation (LOQ, RS/N = 10）was 5 μg/kg. The recoveries at different spiked levels were between 81.10% and 107.39% with relative standard deviation (RSD) ranging from 1.97% to 9.73%. This method has the advantages of accurate results, small background interference, simple operation, good stability and short pretreatment time, and is useful for the detection of nonylphenol in milk powder.

Key words: nonylphenol; high performance liquid chromatography-tandem mass spectrometry; milk powder; solid phase extraction column

摘要： 建立乳粉中壬基酚的高效液相色谱-串联质谱法检测方法。采用乙腈提取，通过固相萃取柱净化，Waters ACQUITY UPLC BEH C18色谱柱（2.1?mm×50?mm，1.7?μm）分离，采用电喷雾电离负离子模式，多反应监测条件下进行测定，内标法定量。结果表明：在1～200?ng/mL线性范围内，壬基酚标准曲线线性关系良好（R2＞0.99），方法检出限（RS/N=3）为2?μg/kg，定量限（RS/N=10）为5?μg/kg；在不同加标浓度下，加标回收率为81.10%～107.39%，相对标准偏差为1.97%～9.73%。该方法具有结果准确、本底干扰小、操作简便、稳定性好、前处理时间短等优点，适用于乳粉中壬基酚的检测。

关键词: 壬基酚；高效液相色谱-串联质谱；乳粉；固相萃取柱