de Jong Jacob, Tomassen Marinka, Driessen Jaap, Keukens Henk, Hans-Artur Putzka, Brambilla Glanfranco
RIKILT-Institute of Food Safety, Wageningen, The Netherlands.
J AOAC Int. 2004 Nov-Dec;87(6):1269-77.
A reversed-phase liquid chromatography method for nicarbazin in broiler feeds and premixtures was developed, validated, and interlaboratory studied. The extraction solvent was an acetonitrile-methanol (1 + 1) mixture. For feedingstuffs, water was also added. The 4,4'-dinitrocarbanilide moiety of nicarbazin was detected at a wavelength of 350 nm. Recovery was > or =87%. At 20 mg/kg, the repeatability was 0.7% and the within-laboratory reproducibility was 2.7%. The limit of determination was <20 mg/kg. Other feed additives did not interfere in the assay that proved to be applicable to broiler feeds from different European Union countries. In an interlaboratory study, 4 positive broiler feeds, 1 blank pig feed, and 1 broiler premixture were analyzed by 19 laboratories using the method developed in this study. The relative standard deviation for repeatability (RSDr) of the feedingstuffs (20-240 mg/kg) varied between 2.6 and 10.2%. The HORRAT ranged between 0.70 and 1.22. Recoveries were 91-108%. Three laboratories detected small signals in the blind blank samples, ranging from 0.4 to 2 mg/kg. For the premixture, acceptable results for reproducibility could only be obtained after the sample weight and volume of extraction had been doubled. To avoid excessive dilution of the extracts, the range of the calibration curve had also been doubled. With this modified method, the RSDr was 5.7% and the HORRAT was 1.95 (10 laboratories).
建立了一种用于测定肉鸡饲料和预混料中尼卡巴嗪的反相液相色谱法，并进行了方法验证和实验室间研究。萃取溶剂为乙腈 - 甲醇（1 + 1）混合物。对于饲料，还添加了水。在350 nm波长下检测尼卡巴嗪的4,4'-二硝基卡巴肼部分。回收率≥87%。在20 mg/kg时，重复性为0.7%，实验室内再现性为2.7%。测定限<20 mg/kg。其他饲料添加剂不干扰该测定，该方法适用于来自不同欧盟国家的肉鸡饲料。在一项实验室间研究中，19个实验室使用本研究建立的方法分析了4种阳性肉鸡饲料、1种空白猪饲料和1种肉鸡预混料。饲料（20 - 240 mg/kg）重复性的相对标准偏差（RSDr）在2.6%至10.2%之间变化。HorRat值在0.70至1.22之间。回收率为91% - 108%。三个实验室在盲样空白样品中检测到小信号，范围为0.4至2 mg/kg。对于预混料，只有在样品重量和萃取体积加倍后才能获得可接受的再现性结果。为避免提取物过度稀释，校准曲线范围也加倍。采用这种改进方法，RSDr为5.7%，HorRat为1.95（10个实验室）。
