Filters cellulose-acetate

In a similar announcement, Eastman Chemical Co. and Rhc ne-Poulenc S.A. have recently formed a 50/50 joint venture to make 59,090 metric tons /yr of cellulose acetate filter tow and fiber by the fourth quarter of 1993 (107). Eastman Chemical Co. aimounced a multimillion doUar expansion of its own filter tow capacity by approximately 11,363 metric tons/yr to be completed by mid-1991. The expansion brings the company s worldwide filter tow capacity up to 154,545 metric tons (108). Eastman Chemical Co. aimounced plans to expand the production of cellulose acetate butryates and cellulose acetate propionates by 20 and 40%, respectively, by mid-1991 (109). 

Chrambach this indicates that the effective protein size for gel filtration is larger than the effective size for gel electrophoresis. They concluded that this could not be accounted for by gel swelling, pH, or ionic strength effects. Biefer and Mason [36] found the constant a in Eq. (93) to be 0.93. They measured the conductance of cellulose acetate filter pads with porosities from 0.5 to 0.9 in solutions of 10 M KCl. 

Charcoal-cellulose acetate filter. N-nitrosodimethy1amine. %-nitrosoethylmethylamine. 8N-nitrosodiethylamine. N-nitrosopyrrolidine. 

Even more promising appears to be the selective reduction of TSNA by perforated cellulose acetate filter tips with higih air dilution. Although the smoker will compensate for the reduction in nicotine by smoking more intensely, it appears that the TSNA yield in smoke does, in this case, not increase to the level observed in smoke of an unperforated filter cigarette. 

Mineral-basal media may be sterilized by autoclaving, but for almost all organic compounds that are used as sources of C, N, S, or P, it is probably better to prepare concentrated stock solutions and sterilize these by filtration, generally using 0.2 pm cellulose nitrate or cellulose acetate filters. The same applies to solutions of vitamins, and to solutions of bicarbonate and sulfide that are components of many media used for anaerobic bacteria. 

Air (particulate lead) Collection of sample onto cellulose acetate filter dissolution in HN03 with heat addition of HCI / H202 and reaction in hydride generator with sodium borohydride to generate lead hydride AAS 8 ng/L 100-101 Nerin et al. 1989... 

As the separation characteristics of liquid chromatographic and electrophoretic techniques markedly differ from each other, combined methods using the advantages of both procedures have been successfully used for the analysis of flavonoids. Thus, the use of CZE-UV, HPTLC-UV and GC-MS for the measurement of flavonoids in seeds and root exudates of Lotus pedunculatus has been reported. The rooting solution and seed exudate were passed through cellulose acetate filters to bind the flavonoids. After extraction,... 

In both procedures purification of the nanoparticles was carried out either by means of filtration of the suspension over a 0.2 pm cellulose acetate filter or by Eppendorf centrifuging for 15 min followed by resuspension in water up to a final suspension of the nanoparticles in PBS buffer (pH 7.2) or in physiological solution. Nanoparticles loaded with a fluorescent marker... 

In the other study. X-ray fluorescence spectroscopy was used to analyze trace element concentrations by observing dusts on 37 ram diameter cellulose acetate filters (20). Twenty-three elutriator and twenty-three area samples from 10 different bales of cotton were analyzed. The average fraction of total dust accounted for by the elements analyzed was 14.4% amd 7.6% for vertical elutriator and area samples, respectively. Although the variation in absolute quantity of atn element was high, the relative abundance of an element was consistent for measurements within a bale. Averaged over all the samples analyzed, calcium was the most abundant element detected (3.6%), followed by silicon (2.9%), potassium (2.7%), iron (1.1%), aluminum (1.1%), sulfur (1.0%), chlorine (0.8%) and phosphorous (0.6%). Other elements detected in smaller aunounts included titanium, manganese, nickel, copper, zinc, bromine, rubidium, strontium, barium, mercury amd lead. 

Air, airborne particulates Collection on cellulose acetate filter digestion with concentrated nitrated and perchloric acids ICP-AES, NIOSH 7300 1 Mg/ sample 105% at 2.5 Mg 97% at 1 mg NIOSH 1994b... 

The initial results were interpreted as evidence of catalytic activity by dithiolenes themselves.211,212 However, Kisch et al.m were soon able to demonstrate that the Zn(mnt)2 complex dianion decomposed to ZnS under these conditions and it is now believed that the dithiolene is only the catalyst precursor and that ZnS is the actual catalyst. The sulfide must be extremely finely dispersed, approaching near homogeneous conditions, because filtration of the solution through a cellulose acetate filter of 0.2 /jm pore size did not reduce the rate of reaction. 

The analysis of aliphatic acids was performed using a P/ACE MDQ capillary electrophoresis instrument equipped with a 60 cm x 50 pm id fused silica capillary (Beckman Coulter, Fullerton, CA). The samples were filtered through a 0.45-gm cellulose acetate filter (Whatman, Maidstone, UK) prior to hydrodynamic injection at 15 psi for 4 s. The voltage was set to 20 kV at reversed polarity. The electrolyte, composed of 5.0 mM trimellitic acid, 50 mM tris(hydroxymethyl)-aminomethane, 1.0 mM tetradecyl-trimethylammoniumbromide, and 0.5 mM calcium chloride, had a pH of 9.8. Before use, it was filtered through a 0.2-gm cellulose nitrate filter and degassed withhelium. Detection was performedby indirect UV absorption at 220 nm. Succinic acid was used as internal standard. 

When applied to suspension cells the acid washing steps may be done by repeated centrifugation but this is tedious and leads to losses of cellular material unless care is taken. Alternatives involve retaining the cells on glass fibre or cellulose acetate filters in a microanalysis filter holder (Millipore Corp. Ltd.) or the cells may... 

After preincubation of the brush border membrane vesicle preparation for 2 h, [2 14 C]urate uptake is initiated by adding 200 pi of incubation medium to 20 pi of the membrane suspension. The incubation medium has the following composition (mmol/1) 150 mannitol, 2 MgS04, 50 potassium phosphate buffer, pH 6.0 or 7.5, 0.02 [2-14 C]urate, and various concentrations of the inhibitor. At 10 s after the addition of the incubation medium, 200 pi portions of the suspension are pipetted onto the center of prewetted cellulose acetate filters kept under suction. The vesicles retaining on the filter are washed immediately with 5 ml of an ice-cold solution containing 150 mmol/1 mannitol and 50 mmol/1 potassium phosphate buffer, pH 6.0 or 7.5, which is used at the same pH as the incubation medium. Preincubations and incubations are performed at 23 1 °C. Each experiment is performed in triplicate. Corrections are made for the radioactivity bound to the filters in the absence of membrane vesicles. The term of the OH gradient-dependent urate uptake is defined as the difference between the uptakes in the incubation medium at pH 6.0 and that at pH 7.5. The OII gradient-dependent urate uptake at 10 s is assumed to present an initial velocity. 

Nongel sieving media have been applied to problems of forensic interest by McCord et al. (1993a), who used the following procedure for buffer preparation 0.1 mAf EDTA was added to 100 mAf Trisma base and 100 mAf boric acid pH was adjusted to 8.7 with cesium hydroxide. Hydroxyethylcellulose was dissolved in this buffer at a concentration of 0.5% (w/v), and the solution was filtered through a 0.45 mm cellulose acetate filter. Prior to analysis, ethid-ium bromide was added to a concentration of 1.27 mAf. Phenylmethyl-coated... 

For immunoassay techniques, cellulose acetate filters offer no advantage over glass fiber filter paper, and the slow flow rate and the handling problems of cellulose acetate when compared with glass fiber make it less suitable for use when large numbers of samples are involved. The retention characteristics of GF/B filter paper are adequate for most immunoassay techniques. However, in receptor assays, the particle sizes are close to the minimum retention size of the GF/B filter paper, and cellulose acetate filters are being used for filtration of these samples. 

Fig. 9.4 The colony lift screen. Step 1 Bacteria are spread on a Supor (low protein binding) filter on YTG -agar plate and grown for lOh at 30°C to form microcolonies. Step 2 The Supor filter is placed on top of cellulose-acetate filter on IPTG containing plate at 30°C for 16 h (induction of scFv-CBD expression). During the induction period the scFv-CBD fusion are secreted, diffuse and bind tightly to the cellulose acetate filter. Step 3 The colonies on Supor filter are saved for recovery later. The cellulose acetate filter is processed with labeled antigen as illustrated in the cartoon. Step 4 Probable binders are identified on the cellulose-acetate filter and colonies picked from the master Supor filter. These candidates are later verified by ELISA for specificity...

Fig. 9.5 Simultaneous identification of binders of two antigens on a single filter, (a) scheme of the screen with two antigens each labeled with a different fluorophore. (b). Similar numbers of colonies from two independent selections (done on each antigen separately) were plated on the Supor master filter (the left half in (b)). The antibodies that diffused down into the cellulose acetate filter were developed with the fluorescently labeled antigens mixed together at 10(lg/ml each. The filters were washed and analyzed using a Typhoon 8600 reader (Molecular Dynamics). The right-hand half in (b) is a mirror image of the left filter with bright spots were green and dimmer spots marked by arrows were red...

On-site determinations of N03 concentrations were made using the Pastel UV at 37 sites in the Weiherbachgraben and Sauruntz sub-basins of the Hardt catchment. Both surface and ground waters were sampled over a two-day field campaign. In addition spot water samples were collected for analysis by ion chromatography in the laboratory. Immediately after collection an aliquot of the water sample was filtered through a 0.45 pm cellulose acetate filter (Millipore) and stored in a polyethylene bottle at 4-8°C until analysis. 

Prehybridization solution is removed from the bag and the hybridization solution is added but probe may be added directly to prehybridization solution (Section 8.1.2). Hybridization buffers should match those used for prehybridization in the case of radiolabeled probes and nitrocellulose membranes. The volume of the hybridization solution should be kept as small as possible. The probe is evenly distributed by massaging the bag and incubating at the proper temperature with agitation. The probe should be clean (spin column, Cameo IIS or Unlflo cellulose acetate filters for radioprobes) and denatured, if necessary, by boiling in TE for 5 min (radioprobes. 

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