QuEChERS结合高效液相色谱-串联质谱法测定饲料中的18种β-兴奋剂

建立了饲料中克仑特罗、莱克多巴胺、喷布特罗、妥布特罗等18种β-兴奋剂的QuEChERS结合高效液相色谱-串联质谱的检测方法。饲料样品加水分散后经4%(v/v)氨水乙腈提取,加入25 mg十八烷基硅烷(C18)和50mg N-丙基乙二胺(PSA)吸附剂分散固相萃取净化后,以高效液相色谱-串联质谱进行定性和定量分析。采用Agilent Zorbax Eclipse XDB-C18(50 mm×4.6 mm,1.8μm)分析柱,以甲醇-0.1%(v/v)甲酸水溶液为流动相进行梯度洗脱,串联质谱在多反应监测(MRM)正离子模式下进行检测,基质外标法定量。结果表明,18种待测物在质量浓度为5~200μg/L范围内线性关系良好,相关系数为0.9912~0.9995;在0.05、0.1、0.5 mg/kg 3个浓度加标水平下,饲料中18种β-兴奋剂的平均回收率为78.4%~107.1%,相对标准偏差(RSD)为3.5%~12.3%,定量限(以信噪比≥10计)均为0.05 mg/kg。该方法准确、灵敏,前处理简单,可作为饲料中克仑特罗等18种β-兴奋剂筛选和确认的检测方法。

Simultaneous determination of 18β-agonist residues in feed using QuEChERS sample preparation and high performance liquid chromatography-tandem mass spectrometry

A multi-residue method was developed for the simultaneous determination of 18 β-agonist residues (clenbuterol, ractopamine, penbutolol, tulobuterol, etc) in feed by using QuEChERS sample preparation and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The feed samples were dispersed by water, then the analytes were extracted with acetonitrile containing 4%(v/v) ammonia and cleaned up by QuEChERS method with 25 mg octadecylsilyl (C₁₈) and 50 mg primary secondary amine (PSA) adsorbents. The separation of compounds was carried on an Agilent ZORBAX Eclipse XDB-C₁₈ column (50 mm×4.6 mm, 1.8 μm) by a gradient elution using methanol-0.1%(v/v) formic acid aqueous solution as mobile phase. The analytes were detected by tandem mass spectrometry under multiple reaction monitoring (MRM) mode with positive electrospray ionization (ESI⁺) and quantified by the matrix-matched external standard method. The results showed that the calibration curves of the 18 β-agonists were linear in the range of 5-200 μg/L with correlation coefficients of 0.9912-0.9995. The average recoveries of the 18 analytes at three spiked levels of 0.05, 0.1 and 0.5 mg/kg ranged from 78.4% to 107.1% with the relative standard deviations (RSDs) of 3.5%-12.3%. The limit of quantification (LOQ, S/N≥10) was 0.05 mg/kg for each analyte . The developed method is simple and sensitive, and can be applied as a screen and confirmatory method for the analysis of β-agonists in feed.