Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509, USA.
J Agric Food Chem. 2010 Jan 13;58(1):101-7. doi: 10.1021/jf903040z.
The recent worldwide shortage of acetonitrile has prompted the development of a new method using methanol as an alternative organic solvent in the extraction and liquid chromatographic analysis of melamine and cyanuric acid that may be present as contaminants in dairy products and pet foods. A simple extraction of melamine and cyanuric acid residues in fortified samples was successfully achieved, using a methanol-water mixture and analysis by isotopic dilution high-performance liquid chromatography-triple-quadrupole mass spectrometry (HPLC-MS/MS). A two-step centrifugation procedure was employed to remove matrix components from extracts. The separation of melamine and cyanuric acid was carried out on a Dionex Acclaim Trinity P1 column, with a methanol and ammonium acetate buffer used as the mobile phase. Excellent linearity was achieved for both the melamine and cyanuric acid calibrations. A variety of dairy products and pet foods were fortified with melamine and cyanuric acid at three levels, 1, 2.5, and 10 microg/g, producing recovery yields of 101-119% for melamine and 84-123% for cyanuric acid. The lower limit of quantification (LLOQ) of melamine was 0.03 microg/g for liquid milk and 0.05 microg/g for dry infant milk formula. The quantitative results were comparable with those derived from previous methods that have been proposed by the U.S. Food and Drug Administration for the screening of melamine and its analogues in foods.
最近全球范围内乙腈短缺，促使人们开发了一种新方法，即在提取和液相色谱分析乳制品和宠物食品中可能存在的三聚氰胺和氰尿酸污染物时，使用甲醇替代有机溶剂。通过使用甲醇-水混合物并通过同位素稀释高效液相色谱-三重四极杆质谱法（HPLC-MS/MS）进行分析，成功地从强化样本中简单提取了三聚氰胺和氰尿酸残留。采用两步离心程序从提取物中去除基质成分。三聚氰胺和氰尿酸的分离在 Dionex Acclaim Trinity P1 柱上进行，使用甲醇和乙酸铵缓冲液作为流动相。三聚氰胺和氰尿酸的校准均具有出色的线性。在三种水平（1、2.5 和 10 μg/g）下，向各种乳制品和宠物食品中添加三聚氰胺和氰尿酸，得到的三聚氰胺回收率为 101-119%，氰尿酸回收率为 84-123%。对于液态奶，三聚氰胺的定量下限（LLOQ）为 0.03 μg/g，对于婴儿配方奶粉，则为 0.05 μg/g。定量结果与美国食品和药物管理局先前提出的用于筛选食品中三聚氰胺及其类似物的方法得出的结果相当。
