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目的建立高效液相色谱-电喷雾串联质谱法同时测定奶及奶制品中双氰胺和三聚氰胺的确证方法。方法样品经2.5%(V/V)甲酸水溶液提取后,用乙腈沉淀蛋白,经微孔滤膜净化,Acquity UPLC BEH Amide色谱柱(100 mm×2.1 mm×1.7mm)分离,含0.1%(V/V)的乙腈-水为流动相,梯度洗脱,采用串联四极杆质谱、电喷雾电离源正离子多反应监测模式检测,外标法定量。结果双氰胺和三聚氰胺浓度在5.0~1000.0μg/L时,线性关系良好(r分别为0.9995和0.9997),双氰胺和三聚氰胺的检出限均为10.0μg/kg;在0.050、1.0和10.0 mg/kg 3个添加水平范围内的平均回收率分别为86.0%~100.0%、90.0%~104.0%和90.0%~100.1%,相对标准偏差在1.06%~7.77%之间;加标样品日内重复测定的RSD分别为2.35%(双氰胺)和3.44%(三聚氰胺),日间重复测定的RSD分别为3.87%(双氰胺)和5.39%(三聚氰胺)。结论该法快速、准确、灵敏,优于传统的HPLC分析方法,适合于生产过程监控和日常检测的高灵敏度确证分析。
Objective To establish a method for simultaneous determination of dicyandiamide and melamine in milk and dairy products by high performance liquid chromatography-electrospray ionization tandem mass spectrometry. Methods After the sample was extracted with 2.5% (V / V) formic acid aqueous solution, the protein was precipitated with acetonitrile and purified by microporous membrane. The sample was separated on a Acquity UPLC BEH Amide column (100 mm × 2.1 mm × 1.7 mm) / V) acetonitrile-water as mobile phase, gradient elution, using quadrupole quadrupole mass spectrometry, electrospray ionization source positive ion multi-reaction monitoring mode detection, external standard method. Results The linear relationship between dicyandiamide and melamine was 5.0 ~ 1000.0μg / L (r = 0.9995 and 0.9997, respectively). The detection limits of dicyandiamide and melamine were both 10.0μg / kg and 0.050,1.0 and 10.0 The average recoveries were within the range of 86.0% -100.0%, 90.0% -104.0% and 90.0% -100.1%, respectively. The relative standard deviations were between 1.06% and 7.77%. The spiked samples were replicated intraday The measured RSDs were 2.35% (dicyandiamide) and 3.44% (melamine) respectively, with RSDs of 3.87% (dicyandiamide) and 5.39% (melamine) for daytime repeated measurements, respectively. Conclusion The method is rapid, accurate and sensitive, which is superior to the traditional methods of HPLC analysis. It is suitable for the high-sensitivity confirmatory analysis of the production process monitoring and routine testing.