A sensitive and reliable method using liquid chromatography–negative electrospray ionization mass spectrometry was developed for the simultaneous determination of chloramphenicol, florfenicol, and thiamphenicol at trace levels in animal feed. The analytes were extracted from grinded feed with ethyl acetate. Further the ethyl acetate was evaporated, residue resuspended in Milli-Q water, defatted with n -hexane, and solid phase extracted using BondELUT C18 cartridges. Separation was carried out on a C6 phenyl column with a mobile phase consisting of 0.1% formic acid in Milli-Q water and acetonitrile. The detector response was linear over the tested concentration range from 100 to 1000 µg kg −1 . The recovery values for all analytes in feed were higher than 79% with RSD for repeatability and reproducibility in the ranges of 4.5–10.9% and 8.4–13.5%, respectively. CCα and CCβ varied between 76.8 and 86.1 µg kg −1 , and between 111.3 and 159.9 µg kg −1 , respectively. The results showed that this method is effective for the quantification of phenicols in non-target feed.

中文翻译：

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液相色谱-质谱法定量分析饲料中痕量苯酚

开发了一种使用液相色谱-负电喷雾电离质谱法的灵敏可靠的方法，用于同时测定动物饲料中痕量水平的氯霉素、氟苯尼考和甲硫霉素。用乙酸乙酯从研磨的进料中萃取分析物。进一步蒸发乙酸乙酯，将残余物重新悬浮在 Milli-Q 水中，用正己烷脱脂，并使用 BondELUT C18 柱进行固相萃取。分离在 C6 苯基柱上进行，流动相由 Milli-Q 水中的 0.1% 甲酸和乙腈组成。检测器响应在 100 至 1000 µg kg -1 的测试浓度范围内呈线性。进料中所有分析物的回收率均高于 79%，RSD 的重复性和再现性范围为 4.5-10.9% 和 8.4-13.5%，分别。CCα 和CCβ 分别在76.8 和86.1 µg kg -1 之间以及111.3 和159.9 µg kg -1 之间变化。结果表明，该方法对非目标饲料中苯酚的定量是有效的。