Heller D N, Lewis K M, Cui W
Center for Veterinary Medicine, U.S. Food and Drug Administration, Laurel, Maryland 20708, USA.
J Agric Food Chem. 2001 Oct;49(10):4597-602. doi: 10.1021/jf0106188.
A procedure has been developed and validated for measuring the concentration of pentobarbital residues in dry, extruded animal feed in the range of 3-200 ng/g (ppb) with an estimated limit of quantitation of 2 ppb. The method was developed for surveillance purposes: to measure the concentration of euthanizing agent which might be present in feeds incorporating rendered products which themselves might include some fraction of euthanized animals. A previously published qualitative procedure was modified by adding isotopically labelled pentobarbital as an internal standard. Dry feed was ground and extracted with methanol. The extract was loaded on a mixed-mode (C-18, anion exchange) solid-phase extraction cartridge designed for barbiturate residues. Pentobarbital was eluted and derivatized for gas chromatography/mass spectrometry in positive ion chemical ionization mode. Quantitation was based on the ratio of dimethyl-pentobarbital MH+ (m/z 255) vs dimethyl-pentobarbital-d(5) (m/z 260) in standards and extracts. Accuracy ranged from 112% at 3 ppb to 96% at 200 ppb, with relative standard deviations ranging from 4% at 3 ppb to 2% at 200 ppb.
已开发并验证了一种用于测量干制挤压动物饲料中戊巴比妥残留浓度的方法，该浓度范围为3 - 200纳克/克（ppb），估计定量限为2 ppb。该方法是为监测目的而开发的：用于测量可能存在于含有加工产品的饲料中的安乐死剂浓度，而这些加工产品本身可能包含一部分已安乐死动物的成分。通过添加同位素标记的戊巴比妥作为内标，对先前发表的定性方法进行了修改。将干饲料研磨并用甲醇提取。提取物加载到专为巴比妥类残留设计的混合模式（C - 18，阴离子交换）固相萃取柱上。戊巴比妥被洗脱并衍生化，用于正离子化学电离模式的气相色谱/质谱分析。定量基于标准品和提取物中二甲戊巴比妥MH +（m/z 255）与二甲戊巴比妥 - d(5)（m/z 260）的比率。准确度范围从3 ppb时的112%到200 ppb时的96%，相对标准偏差范围从3 ppb时的4%到200 ppb时的2%。
