Thalmann Alfred, Wagner Klaus, Tomassen Marinka, Driessen Jaap, de Jong Jacob
State Agricultural Testing and Research Station Augustenberg (LUFA), 76227 Karlsruhe, Germany.
J AOAC Int. 2004 Nov-Dec;87(6):1278-86.
A reversed-phase liquid chromatography (LC) method for narasin in feedingstuffs and premixtures was developed, validated, and interlaboratory studied. The extraction solvent was methanol-K2HPO4 solution (9 + 1, v/v). Narasin was detected at 600 nm after post-column derivatization with dimethylamino-benzaldehyde. Recovery was >90%. The repeatability (RSDr) in feed (20-140 mg/kg) ranged between 1.2 and 10.5%; the within-laboratory reproducibility (RSD(R)) ranged between 2.2 and 4.9%. The limit of determination was <20 mg/kg. Other feed additives did not interfere in the assay. The method showed ruggedness against changes in the composition of extraction solvent, eluent, and conditions for post-column reactions. In an interlaboratory study, 5 broiler feeds (4 positive, 1 blank) and 1 premixture were analyzed by 13 laboratories. The RSDr of the feedingstuffs (20-120 mg/kg) varied between 2.17 and 7.57%. The HORRAT ranged between 0.77 and 0.88, with recoveries between 82 and 104%. One laboratory detected small signals in the blank sample, calculated as 0.6 and 2.8 mg/kg. For the premixture, acceptable results for reproducibility could only be obtained after modification of the method: the RSDr was 4.42% and the HORRAT was 1.56 (12 laboratories).
建立了一种用于饲料和预混料中甲基盐霉素的反相液相色谱（LC）方法，并进行了验证和实验室间研究。萃取溶剂为甲醇 - K2HPO4溶液（9 + 1，v/v）。用二甲基氨基苯甲醛进行柱后衍生后，在600 nm处检测甲基盐霉素。回收率>90%。饲料中（20 - 140 mg/kg）的重复性（RSDr）在1.2%至10.5%之间；实验室内再现性（RSD(R)）在2.2%至4.9%之间。测定限<20 mg/kg。其他饲料添加剂不干扰该测定。该方法对萃取溶剂、洗脱液的组成以及柱后反应条件的变化具有耐用性。在一项实验室间研究中，13个实验室分析了5种肉鸡饲料（4种阳性，1种空白）和1种预混料。饲料（20 - 120 mg/kg）的RSDr在2.17%至7.57%之间。HorRat值在0.77至0.88之间，回收率在82%至104%之间。一个实验室在空白样品中检测到小信号，计算值为0.6和2.8 mg/kg。对于预混料，只有在方法修改后才能获得可接受的再现性结果：RSDr为4.42%，HorRat为1.56（12个实验室）。
