超高效液相色谱-串联质谱法测定液态乳中的壬基酚

利用超高效液相色谱-串联质谱（ultra performance liquid chromatography-tandem mass spectrometry，UPLCMS/MS）技术建立液态乳中壬基酚（nonylphenol，NP）的检测方法。使用乙腈作为提取溶剂，加饱和氯化钠溶液使乙腈和水分层，采用ProElut PAEs Glass玻璃固相萃取小柱净化，Waters ACQUITY UPLC BEH C18色谱柱（2.1 mm×50 mm，1.7 μm）分离，以0.1%氨水-甲醇流动相体系进行梯度洗

Determination of Nonylphenol in Liquid Milk by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

A method for the determination of nonylphenol in liquid milk by using ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed. Samples were extracted using acetonitrile as extraction solvent and the organic phase was separated from the aqueous phase by adding saturated sodium chloride solution. The analyte was cleaned up using a ProElut PAEs Glass solid-phase extraction catridge and then separated on a Waters ACQUITY UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) using gradient elution with 0.1% ammonia water-methanol as mobile phase. The detection was performed by negative electrospray ionization under the multiple reaction monitoring mode and the quantitation was carried out by an internal standard method. The results showed a good linear relationship (R2 > 0.990) in then range from 1 to 200 ng/mL. The limit of detection（LOD, RS/N = 3）was 2.0 μg/kg and the limit of quantitation (LOQ, RS/N = 10）was 5 μg/kg. The recovery rate of the method for spiked samples was between 74.8% and 111.5% with relative standard deviation of 3.3%-9.0%. In general, the method was accurate, simple and reproducible and exhibited low background inference and it was thus suitable for the analysis of nonylphenol in liquid milk.