Stout S J, Wickremesinhe E, daCunha A R, Khunachak A
American Cyanamid Company, Agricultural Products Research Division, Princeton, NJ 08543-0400, USA.
J AOAC Int. 2000 Nov-Dec;83(6):1446-50.
Moxidectin, a potent new endo- and ectoparasitic agent, is determined in cattle tissues by liquid chromatography (LC) with fluorescence detection. The original confirmatory method for moxidectin in cattle fat, the target tissue for regulatory purposes, was LC with mass spectrometry (MS) using thermospray (TSP) ionization and selected ion monitoring. As newer ionization techniques for LC/MS made TSP obsolete and with the availability of a new generation of benchtop LC/MS instrumentation, the confirmation of moxidectin in cattle fat was re-evaluated. The ionization techniques of atmospheric pressure chemical ionization versus electrospray ionization, the detection techniques of single-stage MS versus tandem MS, and the instrumentation of ion trap versus quadrupole were investigated. The final confirmatory method was based on full-scan single-stage MS. Even with full-scan detection, the analysis required at least 10-fold less extract than the original TSP method. The applicability of this new confirmatory method was demonstrated on both ion trap and quadrupole instruments.
莫西菌素是一种新型强效体内外寄生虫驱杀剂，采用液相色谱（LC）结合荧光检测法测定牛组织中的莫西菌素含量。用于监管目的的目标组织——牛脂肪中莫西菌素的原始确证方法是液相色谱-质谱联用（LC/MS），采用热喷雾（TSP）电离和选择离子监测。随着液相色谱-质谱联用技术中更新的电离技术使热喷雾技术过时，以及新一代台式液相色谱-质谱联用仪器的出现，对牛脂肪中莫西菌素的确证方法进行了重新评估。研究了大气压化学电离与电喷雾电离这两种电离技术、单级质谱与串联质谱这两种检测技术以及离子阱与四极杆这两种仪器设备。最终的确证方法基于全扫描单级质谱。即使采用全扫描检测，该分析所需的提取物也比原始热喷雾方法至少少10倍。这种新的确证方法在离子阱和四极杆仪器上均得到了验证。
