Filtration, millipore

The sampling of solution for activity measurement is carried out by filtration with 0.22 pm Millex filter (Millipore Co.) which is encapsuled and attached to a syringe for handy operation. The randomly selected filtrates are further passed through Amicon Centriflo membrane filter (CF-25) of 2 nm pore size. The activities measured for the filtrates from the two different pore sizes are observed to be identical within experimental error. Activities are measured by a liquid scintillation counter. For each sample solution, triplicate samplings and activity measurements are undertaken and the average of three values is used for calculation. Absorption spectra of experimental solutions are measured using a Beckman UV 5260 spectrophotometer for the analysis of oxidation states of dissolved Pu ions. 

Experiments in 500 ml Erlenmeyer flasks and Fernbach flasks contained 200 ml and 1 L of EPl and EP2 medium respectively. Inocuia added to these cultures was 2 ml of spore suspension (5.0 optical density at 540 nm) for each 100 ml EP medium. All cultures were grown at 37°C in a shaking incubator (New Brunswik Sci. Co., USA), at 200 rpm. Then 10 ml of sample were withdrawn each 24 h during fermentation and immediately filtered through Millipore membranes of 0.45 pm pore size these cell-free filtrates were used for enzymatic assays and extracellular protein determinations by the Lowry method (14). Experiments in the 14 L fermentor (Microgen Fermentor New Brunswik Sci. Co., USA) were carried with lOL of fermentation medium EP2 and inoculum added was IL of mycelium grown 24 h in... 

Instead of scraping and manual collection of the adsorbent, the band can be sucked off the plate with a Vacuum-cleaner -type apparatus. Dekker [50] described an apparatus for the isolation of compounds from layers by elution and direct Millipore filtration, and Platt [51] designed a zone collector that used vacuum to transfer separated zones from layers direcdy to vials for hquid scintillation counting of radioactivity. 

Filter IL of water sample through a filter paper. Place an Empore extraction disk in a Millipore extraction funnel. Rinse the disk with 10 mL of ethyl acetate, dichloromethane, and acetonitrile, successively. Dry the disk under vacuum and then rinse the disk with 10 mL of methanol and 20 mL of deionized water by vacuum filtration. Pass the prefiltered sample through the disk and elute alanycarb with two portions of 10 mL of acetonitrile. Transfer the eluates through anhydrous sodium sulfate into a 50-mL flask. Remove acetonitrile by rotary evaporation. Dissolve the residue in 1 mL of acetonitrile. 

Commercial dead-end filtration cells are available from Millipore [12] suitable for ultrafiltration (Figure 4.4, e.g. model 8003 and 8010) and from Schleicher Schuell [13] (Figure 4.5) applicable for ultra- and nanofiltration. 

Both the hydrochloric acid and sodium borohydride contributed to the blank. The Sb (V) in the 12 N hydrochloric acid was removed by uptake on a Dowex 1-X8 anion exchange resin. Sodium borohydride was purified, after dissolution, by addition of 0.5 ml sodium hydroxide (50%) to 200 ml of 5% sodium borohydride, and subsequent filtration through a hydrochloric acid precleaned 0.45 pm Millipore membrane. 

After adjusting to 2 mol 1 1 in hydrochloric acid, 500 ml of the sample is adsorbed on a column of Dowex 1-XS resin (Cl form) and elution is then effected with 2 M nitric acid. The solution is evaporated to dryness after adding 1M hydrochloric acid, and the tin is again adsorbed on the same column. Tin is eluted with 2 M nitric acid, and determined in the eluate by the spectrophotometric catechol violet method. There is no interference from 0.1 mg of aluminium, manganese, nickel, copper, zinc, arsenic, cadmium, bismuth, or uranium any titanium, zirconium, or antimony are removed by ion exchange. Filtration of the sample through a Millipore filter does not affect the results, which are in agreement with those obtained by neutron activation analysis. 

Poly(diallydimethylammonium chloride) (PDDA) was purchased from Aldrich Chemical Co. 2-Morpholinoethanesulfonic acid (MES) was from Wako Pure Chemical Industries Ltd. Poly(butylviologen) (PBV), shown in Scheme 1, was synthesized according to literature method and checked by HNMR [7], Ultrapure water (18.3 M l) was prepared with a Milli-Q filtration unit of Millipore Corp. 

All of the LC extracts were dissolved in ethanokhexane (1 1) by nsing 1% Tween 80 solntion at a final concentration of 1,024 pg/ml and sterilized by filtration nsing 0.22 pm Millipore (MA 01730, USA) and nsed as the stock solntions. Standard antibacterial powders of ampicillin (AMP, Fako), ofloxacin (OFX, Hoechst Marion Ronssel), and also standard antifnngal powders of ketoconazole (KET, Bilim) and... 

A few other players in the nuclear membranes activity also developed inorganic membranes for the filtration of liquids. This was the case with Norton-USA who with the know-how of Euroceral developed MF membranes made of an 0-AI2O3 tubular support with an a-Al203 layer. The inner tube diameter was 3 mm and the outer diameter 5 mm. In 1988-1989, Norton also produced the multichannel membrane elements. These membranes produced by Norton are now sold by Millipore under the trademark Ceraflo . 

Each individual composite disk specimen was immersed in a 100 mL NaCl solution [HEPES-buffered (pH = 7.4), 240 mOsm/kg, 37°C, continuous magnetic stirring] for up to 264 h. Aliquots were taken at regular time intervals, filtered (Millex GS filter assemblies Millipore, Bedford, MA), and the filtrates analyzed for Ca + (AAS) and PO4 (UV). Upon completion of the immersion tests, the disks were removed, dried, and again characterized by XRD. Variations in the total area of disk surface (A) exposed were taken into account and Ca + and P04 values normalized to an average surface area of 500 mm. ... 

Filtration device with 0.45-pm membrane (Millipore, Bedford, MA). 

Water samples deserve some special attention despite of the apparent simplicity of their analysis. One reason is that, depending upon the source, water samples will have varying degrees of particulates. Most pollution surveys require filtration through a 0.45 M Millipore filter. In the event that filtration is omitted deliberately or unknowin gly, such particulates are entrained into the plasma, dissociated, and excited in the intense heat of the source. The efficiency of entrainment and nebulization depends on the specific nebulizer used, as well as the particle-size distribution. These in turn effect the degree of dissociation in the plasma. Thus, it is important to ensure that water samples are properly prepared. 

Figure 4. The transport of by Chlorella under Os stress A. Control efflux from pre-loaded cells. A culture of 38°C-grown C. sorokiniana was preloaded with for 24 hrs. Cells were concentrated by centrifugation, washed, and resuspended as described in Figure 1, and assayed for Rfo loss by millipore filtration. The cells were dried, bleached, and counted by liquid scintillation as described by Fredrick and Heath (24). B. Influx into cells. A culture of exponentially growing C. sorokiniana was centrifuged, washed, resuspended in the Tris-Cl solution (see Figure 1) plus 100 fjM KCl, and placed in a 38°C water bath. At time intervals after RB addition, samples of cells were assayed as described in A.

Tanks are filled with chloride-free water obtained by filtration through 5 [tm activated carbon cartridges (Millipore). 

Platinum was introduced on the activated support by a competitive cation exchange technique. An amount of 100 g of a 8 wt% Pt solution of platinumtetrammine hydroxide (Johnson Matthey) was added dropwise to a suspension of 40 g graphite in 800 ml 1 M ammonia (Merck p.a.) and stirred at ambient temperature for 24 hours. The catalyst was subsequently separated by filtration on a Millipore filter (HV 0.45m), washed with distilled water and dried in a vacuum oven at 373 K. The dried catalyst was reduced in flowing hydrogen at 573 K for 2 hours and stored under air before use. 

Functionality Analysis. Solubility was determined on 1% (w/v) dispersion of protein in 0.2 M phosphate buffers at a pH of 3.0 to 8.0. After stirring for 0.5 hr, the dispersion was filtered (0.45 /xm. Millipore), and the filtrate was analyzed for protein by the BCA method (21). Emulsifying activity index (EAI), expressed as interfacial area/unit weight protein (mVg) / was assessed by the turbidometric method of Pearce and Kinsella (22). 

Figure 3. Breakthrough of Hg-195m. After 10 elutions, the breakthrough fluctuates between 1.1 yCi/mCi of Au-195m and 0.5 yCi/mCi of Au-195m. Significant effect is observed after Millipore filtration on day 1 and 4.

Oxidized samples are filtered in Millipore Ultrafilter with a 10,000-MW cut-off (Mil-lipore) by centrifugation at 5000 xg for 30 min. The clear filtrate is injected into the HPLC system (see below). 

Reaction mixture 25 pi of freshly prepared 2 x reaction buffer, 15 pi of water, and 10 pi of filtered cell or tissue lysate (total volume of 50 pi). The reaction mixture is incubated for 30 min at 37°C in the dark, followed by adding 10 pi of oxidation solution. After oxidation for 30 min in the dark at room temperature, 10 pi of 1% ascorbic acid is added, mixed, and centrifuged for 20 min at 14,000 xg through a Micron 10,000 filter (Millipore, Ultracel YM-10). The filtrate is analyzed by HPLC (ideally only 20 pi of a 1 2 dilution with water are injected into the HPLC system). The starting lysate of 10 pi was diluted sevenfold. 

Fifty-microlitre aliquots of standards, QC material or neat CSF are injected directly onto the F1PLC system. Blood-contaminated CSF should be filtered using a 10,000-molecular-weight (MW) centrifugal filtration system (e.g. Millipore Ultrafree-MC centrifugal filters) prior to injection. 

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