全自动固相萃取-HPLC测定生鲜肉中的四环素类抗生素

对采用固相萃取技术萃取的鸡肉和猪肉样品进行净化处理,然后采用高效液相色谱对其中的四环素类抗生素进行同时检测。试验得到土霉素、四环素和金霉素3种四环素类抗生素在鸡肉中的加标回收率分别为87.4%～97.9%、89.2%～92.7%和89.7%～99.4%,猪肉中的加标回收率分别为83.9%～97.9%、90.6%～108.0%和98.1%～109.3%。

Composite Model of Interracial Stepwise Ion/Coordination Particle Exchange-Electrostatic Exchange——Ionic Strength Effect on the Interaction Between Minor Metal Ion and Solid Particle in Seawater

It is the first time in experiment that we have found that the ionic strength effects on E(%)-pH curves of the systems with clay minerals as solid particles and those systems with hydrous oxides as solid particles, are "right-left shift phenomenon" and "left monodirectional shift phenomenon", respectively.The corresponding ionic strength effects on isotherms are "downward-upward shift phenomenon" and "upward monodirectional shift phenomenon", respectively.All the four phenomena are consistent with each other.In order to explain the above phenomena, the composite model of interracial ion/coordination particle exchange-electrostatic exchange is put forward to make a unified explanation and quantitative treatment.From the structures of the two kinds of materials——clay minerals and hydrous oxides, we know that the former has two kinds of exchange actions, i.e. when one increases,the other decreases, which makes the position of curves shift didirectionally,while the latter only has interfacial stepwise