Berardi Giorgio, Bogialli Sara, Curini Roberta, Di Corcia Antonio, Laganá Aldo
Dipartimento di Chimica, Università La Sapienza, Piazza Aldo Moro 5, 00185 Roma, Italy.
J Agric Food Chem. 2006 Jun 28;54(13):4537-43. doi: 10.1021/jf060545y.
Several sulfonamide antimicrobials (SAAs) are largely used in veterinary medicine. A rapid, specific, and sensitive procedure for determining 12 SAAs in cheese is presented. The method is based on the matrix solid-phase dispersion technique followed by liquid chromatography (LC)-tandem mass spectrometry (MS) equipped with an electrospray ion source. Target compounds were extracted from Mozzarella, Asiago, Parmigiano, Emmenthal, and Camembert cheese samples by 6 mL of water modified with 10% methanol and heated at 120 degrees C. The addition of methanol to hot water served to improve remarkably extraction yields of the most lipophilic SAAs, that is, sulfadimethoxine and sulfaquinoxaline. After acidification and filtration, 100 microL of the aqueous extract was injected in the LC column. MS data acquisition was performed in the multireaction monitoring mode, selecting two precursor-to-product ion transitions for each target compound. Methanol-modified hot water appeared to be an efficient extractant, because absolute recovery ranged between 67 and 88%. Using sulfamoxole as surrogate analyte, recovery of the 12 analytes spiked in the five types of cheese considered at the 50 ng/g level ranged between 75 and 105% with RSD not higher than 11%. Statistical analysis of the mean recovery data showed that the extraction efficiency was not affected by the type of cheese analyzed. This result indicates this method could be applied to other cheese types not considered here. The accuracy of the method was determined at three spike levels, that is, 20, 50, and 100 ng/g, and varied between 73 and 102% with relative standard deviations ranging between 4 and 12%. On the basis of a signal-to-noise ratio of 10, limits of quantification were estimated to be <1 ng/g.
几种磺胺类抗菌药物（SAAs）在兽医学中被大量使用。本文介绍了一种用于测定奶酪中12种SAAs的快速、特异且灵敏的方法。该方法基于基质固相分散技术，随后采用配备电喷雾离子源的液相色谱（LC）-串联质谱（MS）。通过用10%甲醇改性的6 mL水从马苏里拉奶酪、阿西亚戈奶酪、帕尔马干酪、埃门塔尔奶酪和卡门培尔奶酪样品中提取目标化合物，并在120℃下加热。向热水中添加甲醇显著提高了亲脂性最强的SAAs（即磺胺二甲氧嘧啶和磺胺喹恶啉）的提取率。酸化和过滤后，将100 μL水相提取物注入LC柱。MS数据采集在多反应监测模式下进行，为每种目标化合物选择两个前体离子到产物离子的跃迁。甲醇改性的热水似乎是一种有效的萃取剂，因为绝对回收率在67%至88%之间。使用磺胺恶唑作为替代分析物，在50 ng/g水平下添加到五种奶酪中的12种分析物的回收率在75%至105%之间，相对标准偏差不高于11%。平均回收率数据的统计分析表明，提取效率不受所分析奶酪类型的影响。这一结果表明该方法可应用于本文未考虑的其他奶酪类型。该方法的准确度在三个加标水平（即20、50和100 ng/g）下测定，变化范围在73%至102%之间，相对标准偏差在4%至12%之间。基于信噪比为10，定量限估计<1 ng/g。
