Heller David N, Nochetto Cristina B
Center for Veterinary Medicine, U.S. Food and Drug Administration, Laurel, Maryland 20708, USA.
J Agric Food Chem. 2004 Nov 17;52(23):6848-56. doi: 10.1021/jf040185j.
A method was developed that is suitable for screening eggs for a variety of nonpolar residues in a single procedure. Residues are extracted by silica solid-phase extraction (SPE). Analysis is conducted via reverse-phase gradient liquid chromatography, electrospray ionization, and tandem ion trap mass spectrometry. For screening purposes (based on a single precursor-product ion transition) the method can detect ionophore (lasalocid, monensin, salinomycin, narasin) and macrolide (erythromycin, tylosin) residues in egg at approximately 1 ng/mL (ppb) and above and novobiocin residues at approximately 3 ppb and above. Conditions are described for confirmatory analysis based on multiple ions in the product ion spectrum. The extraction efficiency for ionophores was estimated at 60-85%, depending on drug. Recovery of macrolides and novobiocin was not as good (estimated at 40-55% after a hexane wash of the final extract was included), but the method consistently screened and confirmed these residues at concentrations below the target of 10 ppb. The method was applied to eggs from hens dosed with each drug individually. Lasalocid was found to have the highest probability of detection in eggs based on its high ionization efficiency and higher rate of deposition relative to the other drugs. The method is part of a larger scheme to provide surveillance methods for a wide variety of drug residues in eggs.
开发了一种适用于在单一程序中筛选鸡蛋中多种非极性残留物的方法。残留物通过硅胶固相萃取（SPE）进行提取。分析通过反相梯度液相色谱、电喷雾电离和串联离子阱质谱法进行。出于筛选目的（基于单一前体-产物离子跃迁），该方法能够检测鸡蛋中离子载体（拉沙洛西、莫能菌素、盐霉素、那拉菌素）和大环内酯类（红霉素、泰乐菌素）残留物，检测限约为1 ng/mL（ppb）及以上，新霉素残留物检测限约为3 ppb及以上。文中描述了基于产物离子谱中多个离子进行确证分析的条件。离子载体的提取效率估计为60 - 85%，具体取决于药物。大环内酯类和新霉素的回收率较差（在对最终提取物进行己烷洗涤后估计为40 - 55%），但该方法能够始终如一地在低于10 ppb的目标浓度下筛选和确证这些残留物。该方法应用于单独用每种药物给药的母鸡所产的鸡蛋。基于其高电离效率和相对于其他药物更高的沉积率，发现拉沙洛西在鸡蛋中的检测概率最高。该方法是为鸡蛋中多种药物残留提供监测方法的更大方案的一部分。
