Capsule filters

O. 2-pm CritiCap Supor capsule filter (Pall Corporation) into the 1-1 polycarbonate bottle under class-100 filtered air. Subsamples of this 0.2-pm filtered station B seawater were collected for subsequent iron measurements, which confirmed that dissolved Fe concentrations were relatively low (0.17 0.1 nM, n = 4). Based on the concentrations of FeCl3 (11.65 pM) and EDTA (11.71 pM) in the LI medium, the resultant 1-1 inoculum of colonial P. antarctica had initial dissolved Fe and EDTA concentrations of approximately 1.42 and 1.25 nM, respectively. 

P. antarctica inoculum was added to 37.8 1 of station B seawater (-0.17 nM dissolved Fe) that had been filtered (0.2 pM Supor capsule filter) then chilled to 0°C in an acid-cleaned 50-1 polyethylene carboy. The calculated dissolved Fe concentration in the resulting large-volume P. antarctica inoculum was -0.20 nM, which was subsequently confirmed by measurement of 0.22 0.00 nM (n = 2) dissolved Fe in filtered subsamples, whereas the final concentration of EDTA in this solution was negligibly low... 

J,m pore-size capsule filter. Samples analyzed for cations were acidified to a pH of about two in the field with ultra pure HNO3. Samples for analysis of nitrogen species and phosphate were collected in opaque plastic bottles and chilled to about 3 °C. Urrfiltered samples also were collected, primarily for analysis of arsenic and iron. 

The fact that additives are responsible for most of the lead content in the air, in dust and even in most of our food has allowed to estimate, as a result of a study of the intake by the human organism, that at least 60 per cent of the lead in the body comes from lead alkyls. Other food or food related sources (tinned foods, capsules, filters, water pipes) play a much less important role than is generally believed. In areas where the traffic is important the contribution of the motor vehicle can account for... 

DNA from the capsule filters was extracted for whole community 16S rDNA and urease gene characterization using a umdified sucrose lysis filter extraction method (P, 10). Briefly, 40 mL of lysis buffer (20 mM EDTA, 400MNaCl, 50 mM Tris, and 0.75 M sucrose, pH 9), 4 mL 10% SDS, and... 

Membrane filter units for pharmaceutical use are available as disc filter, cartridge filter or capsule filter. 

In a capsule filter, the filter membrane and filter case of hard plastic are provided as a whole. Also in a capsule filter, the membrane filter is folded, thereby creating a relatively large filtering surface area. In practice, capsule filters have replaced, for a part, the larger disc filters. They have a filtering surface area of approx. 0.015 m to 0.2 m. An example of a capsule is shown in Fig. 30.10. 

Equally, there are one or two types of replaceable element filter that do not fit the precise definition of a cartridge filter given above, yet are included here because of their similarity of function. These are the capsule filters, much used in laboratories and small-scale production processes such as are involved in the pharmaceutical and life science sectors, and the polymer melt filters, employed to ensure the freedom from blockage of extrusion nozzles for polymer fibres and filaments. 

Similar in principle to the cartridge filter, by virtue of being used until full of collected solids and then cleaned or discarded, are the small in-line capsule filters, much used in laboratories and the small-scale production processes of the life-science industries. These are made entirely, both housing and filter medium, of a polymer suitable to the operating conditions. They take the form of short cylindrical housings (with a length of the same order as the diameter), closed at each end, except for a nipple or nozzle that can be connected to a plastic flow line. 

Somewhat akin to the capsule filter in operating principle, although very different in construction and operating conditions, are many of the filters used to remove contaminants from the flow of molten polymer on its way to an extrusion nozzle. 

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