European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, B-2440 Geel, Belgium.
J Pharm Biomed Anal. 2011 Feb 20;54(3):526-34. doi: 10.1016/j.jpba.2010.09.038. Epub 2010 Oct 8.
A fit to purpose multi-analyte method for the official control of six coccidiostats (monensin sodium, salinomycin sodium, narasin, lasalocid sodium, semduramicin sodium and maduramicin ammonium alpha) at cross-contamination concentration levels in poultry, cattle, pig and calf compound feed by liquid chromatography tandem mass spectrometry (LC-MS/MS) has been developed and in-house validated. The corresponding maximum levels have been recently introduced by European legislation. The method developed involved a simple extraction of the coccidiostats from the feed samples followed by centrifugation and filtration of the supernatants for all matrices. For calf feed an additional de-fattening step of the filtrated supernatants with n-hexane was necessary. The resulting supernatants were submitted to chromatographic analysis. The analytes were quantified by a modified approach of the standard additions technique applied to the extracts, hence allowing a workload comparable to matrix-matched standard calibration curves. A further simplification of this technique was reached by applying the same addition levels of the target analytes for different concentration ranging from 0.5× maximum level up to 2.5× maximum level (universal approach). The concentration independent intermediate precision expressed in terms of relative standard deviation varied between 3 and 12% (except for maduramicin ammonium alpha and semduramicin sodium up to 21%) and the recovery rates ranged from 80 to 111%, depending on the target analyte and matrix. The limits of detection (LOD) and limits of quantification (LOQ) were different for the various analyte/matrix/instrument combinations but all LOQs were in the 0.01-0.65 mg kg(-1) range, hence well below the target concentrations of each analyte. Based on the obtained method performance characteristics the method is considered fit for the intended purpose.
一种专用于目的的多分析物方法，用于通过液相色谱串联质谱法（LC-MS/MS）检测家禽、牛、猪和小牛复合饲料中六种球虫抑制剂（莫能菌素钠、盐霉素钠、那拉菌素、拉沙里菌素钠、萨那霉素钠和马杜霉素铵阿尔法）的交叉污染浓度水平，该方法已经开发并在内部验证。最近，欧洲法规引入了相应的最高水平。所开发的方法涉及从饲料样品中简单提取球虫抑制剂，然后对所有基质的上清液进行离心和过滤。对于小牛饲料，需要用正己烷对过滤后的上清液进行额外的脱脂步骤。所得上清液进行色谱分析。通过对提取物应用标准添加技术的改进方法对分析物进行定量，从而允许与基质匹配标准校准曲线相当的工作量。通过对不同浓度范围（从 0.5×最高水平到 2.5×最高水平）的目标分析物应用相同的添加水平（通用方法），进一步简化了该技术。浓度独立的中间精密度以相对标准偏差表示，范围在 3%至 12%之间（除了马杜霉素铵阿尔法和萨那霉素钠高达 21%），回收率范围在 80%至 111%之间，具体取决于目标分析物和基质。检测限（LOD）和定量限（LOQ）因各种分析物/基质/仪器组合而异，但所有 LOQ 均在 0.01-0.65 mg kg(-1)范围内，远低于每个分析物的目标浓度。基于获得的方法性能特征，该方法被认为适用于预期用途。
