Determination of Ten Kinds of Alpha-2 Agonists Residues in Animal Derived Food by UHPLC-Triple Quadrupole/Composite Linear Ion Trap Mass Spectrometry

[Objectives]The paper was to establish an ultra high performance liquid chromatography-quadrupole/linear ion trap complex mass spectrometry for the determination of 10 kinds ofα2-receptor agonists in animal derived food.[Methods]The samples were extracted with sodium carbonate buffer solution and ethyl acetate,and analyzed by mass spectrometry after solid phase extraction and high performance liquid chromatography separation.[Results]Ten kinds ofα2-receptor agonists showed a good linear relationship in the range of 1-100μg/mL,with the average recovery of over 69%and the relative standard deviation less than 8.32%.The detection limit of 10 kinds of α_(2)-receptor agonists was up to 1μg/kg.[Conclusions]The method has good selectivity and strong anti-interference ability,and can meet the requirements of 10 kinds ofα2-receptor agonists residues in animal derived food.

微多孔结构内流动沸腾及束缚水作用机理:孔隙尺度实验及换热强化

为解决高温部件的散热问题,流动沸腾技术被广泛应用于大功率设备热管理领域,采用多孔涂层和多孔材料可以进一步提高换热效果.与通道中的沸腾过程不同,由于孔隙-喉道结构复杂、流体流动方向随机性大,多孔结构内气固液三相作用规律尚不明确,换热面存在液体蒸干、壁温飞升、材料烧毁等风险.为深入研究微多孔结构内部流动沸腾传热性能,本文搭建了微观模型可视化实验系统,以揭示多孔介质内束缚水的运移机理,并量化相变过程中束缚水的运输形式及其对流动沸腾的影响规律.利用激光诱导荧光和粒子追踪技术获得了液膜在多孔骨架表面的运动速度.通过理论分析,作者发现薄液膜流动受到相邻两液桥间毛细压力差驱动,且毛细效应引起的液桥和薄液膜流动对冷却液向受热表面的输送起着重要作用.进而作者提出了一种孔喉尺寸在10~90μm的不规则多孔结构.该结构实现了传热系数5%~10%的提高,同时压降降低了5%~23%,有助于维持冷却系统高效稳定运行,为多孔材料强化流动沸腾表面结构的设计提供了重要参考.