Department of Food Safety, Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche, Perugia, Italy.
Anal Chim Acta. 2011 Aug 26;700(1-2):167-76. doi: 10.1016/j.aca.2011.02.032. Epub 2011 Feb 18.
A confirmatory method for the determination of residues of eleven coccidiostats including ionophore antibiotics: lasalocid, maduramycin, monensin, narasin, salinomycin, semduramycin and chemical coccidiostats: decoquinate, diclazuril, halofuginone, nicarbazin and robenidine in poultry eggs was developed and validated. The sample was extracted with acetonitrile, defatted with hexane and cleaned-up on a silica SPE cartridge. The analytes were identified and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method performance characteristics required by Commission Decision 2002/657/EC were estimated adopting a more flexible and simple validation design. In this alternative approach the experimental study focuses on a larger dynamic range with progressively increasing validation levels. Each of them presents equal concentrations of all the analytes. On the contrary the classical Decision plan investigates a restricted concentration range necessarily different for each analyte being determined by the individual permitted limit (0.5-1.5 times the permitted limit). As a consequence each validation level involves the simultaneous fortification with complex mixtures containing different concentrations of each analyte. Adopting this alternative strategy the validation of several substances with significantly different permitted limits is considerably simplified and a deeper knowledge of the method is achieved. The results proved that the method enables the confirmation of regulated coccidiostats in eggs at the levels required in the official control of residues (CCα in the range of 2.2-174 μg kg(-1), depending on the coccidiostat). The repeatability (CV(r) in the range of 1.1-19%) and within-laboratory reproducibility (CV(Rw) in the range of 1.8-30%) are also acceptable. The procedure was successfully verified in the proficiency test and implemented in the national residue control plan.
建立并验证了一种可同时确证家禽蛋中 11 种抗球虫药（包括离子载体类抗生素：拉沙里菌素、马杜霉素、莫能菌素、那拉菌素、盐霉素、海南霉素和化学合成抗球虫药：癸氧喹酯、二氯苯胍、常山酮、尼卡巴嗪和罗硝唑）残留的确证方法。采用乙腈提取、正己烷脱脂，经硅胶固相萃取柱净化后，用液相色谱-串联质谱法（LC-MS/MS）进行分析和确证。采用更灵活、简化的验证方案来评估符合欧盟委员会 2002/657/EC 号决议要求的方法性能特征。在该替代方案中，实验研究重点关注更大的动态范围，并逐步提高验证水平。每个验证水平的实验均采用相同浓度的所有分析物进行研究。相比之下，传统的决策方案研究每个待分析物的浓度范围受到各自允许限（0.5-1.5 倍允许限）的限制，因此各验证水平涉及采用不同的浓度范围，需要同时对包含各分析物不同浓度的复杂混合物进行添加。采用这种替代策略，可显著简化不同允许限的多种物质的验证工作，并能更好地了解方法性能。验证结果表明，该方法能够在官方残留监控（取决于抗球虫药，CCα 在 2.2-174μg/kg 范围内）要求的水平上确证鸡蛋中的规定抗球虫药。重复性（CV(r) 在 1.1-19%范围内）和实验室内部再现性（CV(Rw) 在 1.8-30%范围内）也可接受。该方法在能力验证中得到了成功验证，并已纳入国家残留监控计划。
