纯水-超纯水在实验室中的应用分析与机型选配.ppt

* * * * Ultrafilters are polymeric , asymetric membrane , with a very thin (1 μm thickness), active layer at the top and a thicker (100 μm) support below. The thin membrane performs the active separation ; the thicker membrane below acts only as a mechanical support allowing the user to easily handle the membrane. Those membranes may be composite, with the thin (active) and the support layers made of different polymers. Ultrafiltration (UF) membranes operate under pressure : under P , small molecules will be able to cross the thin layer , whereas the large ones will be retained. The cut-off limit is called the Nominal Molecular Weight Limit and is expressed in daltons. This value is used to characterize UF membranes because MW is easier to find in the literature than the molecule dimension. The MW is linked to the molecule size , but other factors are also to consider : the aspect ratio (shape of the molecule : for the same MW, a molecule can have a spherical form or an elongated form. Both molecules will have different retention rates, although their molecular weights are similar) and pH (a variation in pH modifies the tertiary structure of a protein and therefore its shape). * Ichiro Kano制定了标准取样程序。 Kano san Daniel darbouret RD I kano Telis D Stephane M Chemistry qualification technology application Jonathan D VP marketing/RD Yves Gaignet Daniel Danvius Mechanical,electronic chemistry * 水纯化系统与分析仪器的离子水平对比 ppm ppb ppt ppq Milli-Q Advantage Milli-Q Integral Milli-Q Reference Q-POD Element ICP-MS Class 100 Class 10 FAAS ICP-OES GFAA ILC 超痕量元素分析 Q-POD Element剖析图 Quantum ICP Optimizer LW Final Filter POD Base P0DC0VER1 protection against agressive chemicals Tubing for Water Delivery Outlet Solenoid Valve Water to loop (outet) Water from loop (inlet) Milli-Q Integral +