雾非雾
第11楼2012/02/10
QuEChERS就是把提取和净化都放在一步里完成,把SPE填料一股脑都加在一起振荡,然后离心取上清液。
雾非雾
第13楼2012/02/10
9. If samples contain ≥1% fat, add same amount of C18 sorbent as PSA (in addition to PSA) in centrifuge tubes for dispersive-SPE. As the fat content increases, a third phase (lipids) will form in the extraction tube, and the recoveries of nonpolar pesticides will decrease as they partially partition into the lipid layer. The most nonpolar pesticides (e.g. hexachlorobenzene, DDE) will give <70% recovery at ≈5% fat content, but relatively polar GC-amenable and LC-type pesticides are completely recovered at >15% fat (14).
如果样品含脂肪,要用到C18
10. If none of the analytes have planar structures, then GCB can be used to provide additional cleanup, especially for removal of chlorophyll, sterols, and planar matrix co-extractives. In this case, add equal amount of GCB as PSA (in addition to PSA) in centrifuge tubes for dispersive-SPE. Planar pesticides include terbufos,
如果样品含叶绿素、固醇、平面结构的共萃物,就可以用GCB(石墨碳)提供额外的净化。
happy爱米粒
第14楼2012/02/10
呵呵,谢谢雾非雾老师解答,原来是选择性的添加哦