Börner S, Fry H, Balizs G, Kroker R
Federal Institute for Health Protection of Consumers and Veterinary Medicine, Berlin, Germany.
J AOAC Int. 1995 Sep-Oct;78(5):1153-60.
Determination of chloramphenicol (CAP) residues in egg by gas chromatography/high-resolution mass spectrometry (GC/HRMS) with negative chemical ionization and gas chromatography with electron capture detection (GC-ECD) is described. A cleanup based on acetonitrile extraction followed by solid-phase extraction with silica gel and gel filtration columns was developed for extraction of CAP residues from whole egg. For quantitation, the internal standards used were the meta isomer of CAP (m-CAP) for GC-ECD and both m-CAP and deuterium-labeled CAP (D5-CAP) for GC/HRMS. For GC/HRMS, evaluation was performed by selecting characteristic ions at m/z 466 for CAP and m-CAP and at m/z 471 for D5-CAP. Both methods were validated with egg samples fortified at 0.4-2.0 micrograms/kg and lyophilized egg samples from animals treated at the 1 microgram/kg concentration level. The coefficient of variation was below 10%. Limits of detection and quantitation of both methods were about 0.3 and 0.5 microgram/kg, respectively. For confirmation of CAP residues, the relative ion abundance (m/z 466 and 468) was calculated. Further confidence was obtained by comparison of accurate monoisotopic masses from a spectrum library.
描述了采用带负化学电离的气相色谱/高分辨率质谱法（GC/HRMS）和带电子捕获检测的气相色谱法（GC-ECD）测定鸡蛋中氯霉素（CAP）残留量的方法。开发了一种基于乙腈萃取，随后用硅胶和凝胶过滤柱进行固相萃取的净化方法，用于从全蛋中提取CAP残留。定量时，GC-ECD使用的内标是CAP的间位异构体（m-CAP），GC/HRMS使用的内标是m-CAP和氘代CAP（D5-CAP）。对于GC/HRMS，通过选择CAP和m-CAP的m/z 466特征离子以及D5-CAP的m/z 471特征离子进行评估。两种方法均在添加浓度为0.4 - 2.0微克/千克的鸡蛋样品和以1微克/千克浓度水平处理的动物冻干鸡蛋样品上进行了验证。变异系数低于10%。两种方法的检测限和定量限分别约为0.3和0.5微克/千克。为确证CAP残留，计算了相对离子丰度（m/z 466和468）。通过与光谱库中的精确单同位素质量进行比较获得了进一步的确信度。
