Ultra filter

Extraction of Sodium Channel Blockers. A review of published reports shows that methods for purification of sodium channel blockers from bacterial cultures are similar to techniques for isolation of TTX and STX from pufferfish and dinoflagellates (30, 31, 38, 39). Typically, cell pellets of bacterial cultures are extracted with hot 0.1% acetic acid, the resulting supernatant ultra-filtered, lyo-philized, and reconstituted in a minimal volume of 0.1% acetic acid. Culture media can also be extracted for TTX by a similar procedure (Ji). Both cell and supernatant extracts are analyzed further by gel filtration chromatography and other biological, chemical, and immunological methods. Few reports describe purification schemes that include extraction of control samples of bacteriological media (e.g., broths and agars) which may be derived from marine plant and animal tissues. 

The range of whey products that are used include, for example, ultra-filtered and dried WPC, which contains between 20% and 89% protein ion exchange and membrane filtered WPI, which contains at least 90-95% protein (Tunick, 2008) and other whey fraction-enriched products such as p-lactalbumin. These enriched protein whey products can be texturized and used in the manufacture of high-protein content puffed com products (Onwulata et al, 2010). 

The difference between the concentration in the ultra-filtered water and the concentration inside the ultrafiltration cell is therefore a measure of the bound concentration. Griffin and Chian7-7-, Hassett 7-, and Diachenko have used volatilization measurements to determine the extent of binding of pesticides and pollutants to dissolved humic materials. In these experiments either the rate of gas stripping of a compound or its equilibrium vapor pressure is measured in the presence and absence of humic materials. The results obtained can be manipulated in such a way to determine the percentage of the pollutant bound. 

Duplicate samples were processed onshore after a variety of storage procedures. All samples were analysed for copper and iron by GFA-AS. Only samples filtered (< 1 pm), acidified, and stored frozen gave extractable copper and iron results comparable with those for samples extracted immediately after collection. Cold storage with sample acidification in polyethylene containers appeared less satisfactory. Organic extracts from samples processed onboard are best retained in all-Teflon containers pending complete digestion and analysis onshore. Unless clean (ultra-filtered air) conditions can be ensured onboard, the estuarine water samples are best returned in a filtered, acidified, and frozen condition for onshore processing. 

Suspension can be filtered through filtering paper, colloidal dispersions through an ultra filter and true solutions cannot be filtered. A simple version of an ultra filter may look like this a membrane built in as the bottom of a suction funnel which, in its turn, is placed on a suction flask connected to a water jet pump. 

Figure 13.7 An illustration of the varying ability of different nominal molecular weight cut-off ultra filters to separate the small oxidised species of plutonium from the much larger reduced species.

Ultrafiltration Sols pass through an ordinary filter paper. Its pores are too large to retain the colloidal particles. However, if the filter paper is impregnated with collodion and then dipped in HCHO or glacial acetic acid, the pore size is much reduced. Such a modified filter paper is called an ultra-filter. ... 

SF Sludge Free MF Micro Filtered (>120,000 D) UF Ultra Filtered (UF1 ... 

Preclinical Pharmacology. The pharmacokinetics of total and free platinum were determined following oral gavage of JM216 as part of the schedule dependency antitumor experiments described above [20], At doses of 9.5,40 (day 1), 40 (day 5) and 200 mg/kg, non-linear pharmacokinetics were observed, both in terms of total and ultrafilterable platinum. On comparing doses of 9.5 and 40 mg/kg, the AUCs increased by tenfold and out of proportion to the fourfold increase in dose. Conversely, a further fivefold increase in dose to 200 mg/kg (the maximum tolerated for single-dose administration) was accompanied by only a twofold increase in AUC, consistent with saturable absorption. Similar Cmax and AUC values for total and ultra-filterable platinum were obtained on day 5 vs. day 1 for the 40 mg/kg dose level. 

Poduval, V.S., Mistry, V.V. 1999. Manufacture of reduced-fat Mozzarella cheese using ultra-filtered sweet buttermilk and homogenized cream. J. Dairy Sci. 82, 1-9. 

Based on high-molecular-weight fraction of ultra-filtered spent sulfite or kraft liquor. 

Other grades of water may be present in parenteral facilities for use as initial rinses and detergent cleaning. The water utilized for these purposes is generally of relatively low bioburden and is often deionized, softened, ultra-filtered, or in some instances prepared by distillation or reverse osmosis, resulting in chemical purity similar to, if not identical to, WFI. Systems for the preparation of this water are subject to qualification, validation, and routine analysis to assure consistent quality. 

Table I. Molecular weight cutoff of hollow-fiber ultra filters, as related to pore sizeand solution output...

Robinson GB> Walton HA. Glomerular basement membrane as a compressible ultra filter. Microvasc Res 1989 38 36-48. 

MWCO centrifugal ultra-filter (Microcon, Millipore)... 

It should also be noted that the HPLC methods used for vims testing (lEX and RP) are also capable of detecting unexpected (non-viral) proteins, albeit with less sensitivity than this ELISA. AU impurity measures are best applied to the most concentrated in-process samples, specifically at the ultrafiltered bulk virus stage of the process. Taken together, none of these methods has shown any evidence of measurable HCP in the ultra-filtered bulk samples. 

Thorsen T., Harz A., 0degaard H. (1997), Influence of raw water characteristics and membrane pore size on the performance of ultra-filters for NOM (humic substances) removal, IWSA World Congress,... 

One hundred milligram of sorbent (POL or Fe(OH) -POL), previously dried at 100°C for 1 h, was equilibrated at 20°C with 20 mL of 0.03 mol L i KNO3. Solutions of 0.1 mol L individual heavy metals and metalloids (Cu, Zn, or As[V]), adjusted previously to pH 4, were added to each sorbent to give an initial concentration ranging from 0.50 to 7.50 mol L b The pH of each suspension was kept constant for 24 h by addition of 0.1 or 0.01 mol L HCl or KOH. The final suspensions were centrifuged at 10,000 g for 30 min, then ultra-filtered through an ultrafiltration cell (200 mL) equipped with a magnetic stirrer and a membrane with a cutoff of 1000 Da. The final concentration of the metals was determined in the permeated solution by AAS. 

C. F. Nagel, W. D. Bancroft, and N. G. Chatterji and N. R. Dhar showed that the colloidal oxide can be removed by the ultra-filter. W. Biltz and W. Giebel added that the colloidal soln. consists mainly of amicrons, only a small proportion of sub-microns are present. There has been some discussion as to whether the colloidal soln. contains alkali chromite. H. W. Fischer and W. Herz said that peptization, not dissolution, occurs. This is in agreement with hypothesis that the soln. is really the colloidal oxide and the observation of A. B. Northcote and A. H. Church that complete soln. occurs in the presence of 40 per cent, of ferric oxide 12-5, manganous oxide or 20 per cent, of either cobalt or nickel oxide, whereas complete precipitation occurs with 80 per cent, of ferric oxide 60, of manganous oxide or 50, of either cobalt or nickel oxide. Analogous observations were made by M. Prud homme, and M. Kreps. H. B. Weiser and G. L. Mack obtained an organosol in propyl alcohol. 

Inorganic membranes are also available at the upper end of the ultra-filter size range (10-100 nm). 

The crystal suspension was filtered through a membrane filter of 0.45 yun (filtrate A). Part of the filtrate A was further filtered ti ugh an ultra filter (molecular mass cut off 100 kD) (filtrate B). The filtrate A included particles of thermolysin smaller than 0.45 im. The filtrate B mainly consisted of thermolysin molecules because the molecular mass of thermolysin is 34.6 kD. Both filtrates were analyzed by gel filtration lugh performance liquid chromatography (HPLC). In the analysis, the filtrates were adjust to pH 11.0 before use as sample solutions to dissolve the crystals which had precipitated in the filtrates after the filtration. 

Elegir, G., Bussini, D., Antonsson, S., Lindstrom, Z.L. Laccase-initiated cmsslinking of lignocellulose fibres using a ultra-filtered lignin isolated fiom kraft black liquor. Appl. Microbiol. Biotechnol. 77(4), 809-817 (2007)... 

Low-molecular-weight ultra-filtered Kraft liner pulp [21]... 

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