Abstract：
An integrated method combining solid-phase extraction (SPE) with ultra-performance liquid tandem mass spectrometry (UPLC-MS/MS) has been established for quantifying bacitracin (BTC), bacitracin zinc (BZ), and bacitracin methylene disalicylate (BMD) in animal feed. A pretreatment procedure that can effectively, quickly, and simultaneously extract and purify BTC, BZ, or BMD in feed was developed for the first time through the optimization of extraction and SPE conditions. After extraction with acetonitrile + methanol + 15 % ammonia solution (1:1:1, v:v:v) and dilution with EDTA solution (1.5 mmol/L, pH 7.0), a SPE procedure was carried out with C18 cartridge. Following LC-MS/MS analysis utilized a Waters Peptide BEH C18 column with a gradient elution of 0.1 % formic acid in water/acetonitrile with. This method demonstrated a strong linear correlation (R2 > 0.9980) across a 0.01-1.0 mg/L concentration span, based on a matrix-matched standard curve. Satisfactory recoveries of BTC (bacitracin A, B1, B2, and B3), BZ, and BMD in different feeds were obtained from 80.7 % to 108.4 %, with relative standard deviations below 15.7 %. Low limits of quantification ranging within 7.2-20 μg/kg were achieved for bacitracin A, B1, B2, and B3. This method provided an effective and reliable detection method to prevent the addition of BTC and different BTC formulations in feeds.
摘要：
建立了固相萃取(SPE)与超高效液相串联质谱(UPLC-MS/MS)相结合的细菌肽(BTC)定量方法,杆菌肽锌（BZ），动物饲料中的杆菌肽亚甲基二水杨酸酯（BMD）。一个预处理程序，可以有效地，快,同时提取和纯化BTC，BZ,通过优化提取和SPE条件，首次开发了饲料中的BMD。用乙腈+甲醇+15%氨溶液(1:1:1,v:v:v)萃取并用EDTA溶液稀释(1.5mmol/L,pH7.0),用C18药筒进行SPE程序。在LC-MS/MS分析之后,使用Waters肽BEHC18柱,用0.1%甲酸在水/乙腈中的梯度洗脱。该方法在0.01-1.0mg/L浓度范围内表现出很强的线性相关性（R2>0.9980）。基于矩阵匹配的标准曲线。BTC(杆菌肽A，B1、B2和B3)，BZ,不同饲料的骨密度从80.7%到108.4%，相对标准偏差低于15.7%。杆菌肽A的定量下限在7.2-20μg/kg范围内，B1、B2和B3。该方法为防止饲料中添加BTC和不同BTC配方提供了一种有效可靠的检测方法。
