氧化修饰多壁碳纳米管固相萃取-超高效液相色谱/串联质谱法同时测定牛奶中7种雌性激素残留

Simultaneous Determination of Seven Estrogens in Milk by Oxidation Modified Multi-walled Carbon Nanotubes Cleaning with Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

建立了氧化修饰的多壁碳纳米管固相萃取净化-超高效液相色谱/串联质谱技术同时测定牛奶中雌二醇、雌三醇、己烯雌酚、己烷雌酚、己二烯雌酚、炔雌醇、雌酮7种雌性激素残留的方法。样品用乙腈提取,提取液用水稀释后再经过多壁碳纳米管固相萃取小柱净化,净化后的样品采用Waters AtlantisBEH C18色谱柱(100×2.1mm,1.7μm)分离,以乙腈和0.02%氨水溶液为流动相进行梯度洗脱,质谱采用负离子扫描的多反应监测(MRM)模式进行检测,内标法定量。7种雌性激素的线性范围为1~100μg/L,相关系数均大于0.99,方法检出限(S/N≥3)为0.02~0.1μg/kg。将本方法应用于实际样品分析,在低、中、高3个浓度下的加标回收率为86.7%~103.6%,相对标准偏差在1.5%~6.9%之间。结果表明表面氧化修饰的多壁碳纳米管具有较好的净化效果,该方法可快速准确地测定牛奶中雌性激素残留。

A novel method was established for the determination of seven estrogens in milk based on oxidation modified multi-walled carbon nanotubes（MWCNTs） as solid phase extraction sorbent with ultra-performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS）. After extracted by acetonitrile and diluted by water,a step for purification and pre-concentration of the analytes by solid phase extraction with surface modification of MWCNTs was set up. Some important experimental parameters that influence the solid phase extraction were investigated. Then the target analytes were separated by Waters Atlantis BEH column with gradient elution using acetonitrile and 0.02 % ammonia in water as mobile phases, detected by tandem mass spectrometry using multiple reaction monitoring （MRM） in negative ion mode and quantified by internal standard method. The correlation coefficient of each analyte was above 0.99 in the linear range of 1-100 μg/L. The limits of detection（LOD） were 0.02-0.1μg/kg, respectively. The mean recoveries were in the range of 86.7%-103.60%o at three spiked levels of 0.5,5 and 10 μg/kg. The relative standard deviations was less than 6.9%. The proposed method was successfully applied to the analysis of milk samples, which indicated that using surface modification of multi-walled carbon nanotubes as solid phase extraction adsorbent was efficient for purification. It is sensitive, precise and suitable for the confirmation and measurement of estrogens in milk.