In this work, the detection of the furazolidone (FZD) and nitrofurazone (NFZ) metabolites residuals in crucian carp are focused. Crucian carps of identical size were exposed to the mixed nitrofuran antibiotics under optimized bath conditions at a concentration of 50 mg/L, 26 ± 0.5°C for 24 h. Then, liquid chromatography-electrospray ionization-triple quadrupole mass spectrometry (LC–ESI–MSMS) was performed after the drug exposure experiments when the nitrofuran metabolites were enriched in organisms. During the period of 0–144 h, residue levels of the 3-amino-2-oxazolidinone (AOZ) gradually decreased with a prolonged sampling time. The changing trend in semicarbazide (SEM) with the sample collection duration is divided into two stages, and its concentration showed a trend of rising first and then falling. The metabolite concentration–time curve demonstrates that 24 h was used as a sampling time, and fish muscle was selected as tissue samples in the further quantitative study. A novel crucian carp-enrichment procedure coupled to LC–ESI–MSMS quantitative method was further explored based on much metabolite data. According to the exponential curve of the SEM-to-AOZ concentration ratio at a precisely designed FZD-to-NFZ mass ratio, the final FZD content of the veterinary NFZ antibiotics was 0.069 ± 0.005% (in terms of mass).

中文翻译：

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呋喃唑酮和呋喃西林在鲫鱼体内的超高效液相色谱-串联质谱代谢研究

在这项工作中，重点检测鲫鱼中的呋喃唑酮（FZD）和呋喃西林（NFZ）代谢物残留。相同大小的鲫鱼在优化的浴条件下暴露于混合硝基呋喃抗生素，浓度为 50 mg/L，26 ± 0.5°C，持续 24 小时。然后，当硝基呋喃代谢物在生物体中富集时，在药物暴露实验后进行液相色谱-电喷雾电离-三重四极杆质谱 (LC-ESI-MSMS)。在 0–144 小时期间，随着采样时间的延长，3-氨基-2-恶唑烷酮 (AOZ) 的残留水平逐渐降低。氨基脲(SEM)随样品采集时间的变化趋势分为两个阶段，其浓度呈先上升后下降的趋势。代谢物浓度-时间曲线表明，以24 h为采样时间，进一步定量研究选用鱼肌肉作为组织样本。基于大量代谢物数据，进一步探索了一种新型的鲫鱼富集程序与 LC-ESI-MSMS 定量方法的结合。根据精确设计的 FZD 与 NFZ 质量比下 SEM 与 AOZ 浓度比的指数曲线，兽用 NFZ 抗生素的最终 FZD 含量为 0.069 ± 0.005%（以质量计）。