Millipore filter ratio

Tests for filterability of polysaccharides through millipore filters are similar in procedure to screen factor tests for polyacrylamides but yield different interpretations. The millipore filter ratio is defined as the ratio of the time required for the last 250 cc to the first 250 cc of 1000 cc of 500 ppm polymer... 

Table 5 lists the millipore filter ratios and the cumulative flow times of Pfizer s polysaccharide G. The diluents used for these runs were all filtered through a 0.65-micron filter under pressure. The increase in millipore filter ratio between the 100 percent river water (run 10), 80/20 mixture (runs 11, 12, and 13), and a 100 percent formation water (run 14) is consistent with the high retention of polysaccharide G2 in reservoir cores in the 80/20 mixture (321 Ib/acre-ft) and in 100 percent formation water (542 Ib/acre-ft). The results of filterability tests are plotted... 

Table 5. Polysaccharide Millipore Filter Ratios of 500 ppm Active Polysaccharide Product Under a Pressure of 40 psi.

Run No. Broth Cone, (wt %) Diluent (% River % Formation Waters) Viscosity (cp 6 rpm) Flow Time (0 1000 cc) Millipore Filter Ratio... 

Figure 9. Steady-state levels of P-Eat 0 C as a function of GdCl, concentration (24). Reaction mixture contained 50mM tris-HCl, pH 7.0, lOOmM KCl, 100 /xM CaClj, 10 /iM [y-32P]ATP, and 0.3 mg/ml. Ca2 -ATPase. A preincubation for 20 min at 25°C was followed by an incubation of 30 min at 0°C. The reaction was initiated then by addition of [y-32P]ATP and stopped by addition of 5% trichloroacetic acid. The precipitate was retained and washed on Millipore filters and counted for ,2P. The curves shown are calculated by assuming the ratios shown for KI,Ca2 /K,) 7 f, .

The pressure increase in a reaction chamber that contains a porous substrate when a monomer vapor is introduced by a given flow rate can be utilized to calculate the sorption capability of the porous substrate. The pressure buildup curves are shown in Figure 34.6 for Millipore filter and porous polysulfone film. The pressure buildup curve with a porous glass tube is too slow to be presented in the same time scale. From the slope of the linear portion of the pressure buildup curve, the ratio of monomer sorbed/monomer fed into the system is estimated as 0.636 for the polysulfone film, 0.926 for Millipore filter, and 0.9987 for the porous glass tube. 

The surfactant AOT ( purum grade, Fluka) was purified as described by Kotlarchyk 22). The AOT solution was filtered through a 0.2-)im Millipore filter prior to drying in vacuo for eight hours. The AOT was stored in a desiccator over anhydrous calcium sulfate. The molar water-to-AOT ratio (W) was assumed to be 1 in the purified, dried solid (2J ). Water was distilled and filtered through a Millipore Milli-Q system. Ethane, propane ("CP" grade, Linde), and xenon (Research grade, Linde) were used as received. The alkanes had a reported purity of >99% (Aldrich) and were used as received. 

The viscosity of polysaccharides increases with increasing concentration of the biocides. This increase is attributed to cross-linking of the polysaccharide molecules. There were correspondent increases in millipore filtration ratios and filtration times on the addition of biocides or decrease in filterability. A methodology was established to select the most effective biocide on the basis of compatibility with the polymer and the ability to retard metabolic activity in the microflora of the surface and formation waters. 

The copolymer can be further fractionated by precipitation from acetone solution to n-hexanc at room temperature. In each case, only the first fraction should be used to obtain narrowly distributed high molar mass copolymer chains for LLS measurement, ll NMR can be used to characterize the copolymer composition. The ratio of the peak areas of the methine proton of the isopropyl group in NIPAM and the two protons neighboring the carbonyl group in VP can be used to determine the VP content. The composition of each NIPAM-co-VP copolymer was found to be close to the feeding monomer ratio prior to the copolymerization. The nomenclature used hereafter for these copolymers is NIPAM-co-VP/x/y, where x andy are the copolymerization temperature (°C) and the VP content (mol%), respectively. The solution with a concentration of as low as 3.0 x 10-6 g/mL can be clarified with a 0.45 cm Millipore Millex-LCR filter to remove dust before the LLS measurement. The resistivity of deionized water used should be close to 18 M 2 cm. The chemical structure of poly(NIPAM-co-VP) is as follows (Scheme 2). 

Initially, plasma and oral fluid specimens from patients (n = 21) on different antidepressant treatment were collected twice to assess if any of the studied analytes was likely to show a good correlation. The best results were obtained for venlafaxine (%CV for plasma/oral fluid concentrations ratio (f OF/PL) <21%). Therefore, the study was extended for this antidepressant by analysis of oral fluid and plasma specimens from five patients on venlafaxine treatment collected on four occasions. Daily doses of venlafaxine retard formulations were 75 mg for two patients, and 150 mg for the remaining participants. Collection of oral fluid (direct spitting into polypropylene tubes) and plasma (heparinized tubes) specimens was performed, when possible, before the next dose to ensure the drug was in the elimination phase. The dose and the time of collection was the same on the four different occasions for each patient. For the analysis, oral fluid and plasma specimens were centrifuged at 14 x 103 rpm, and 0.2 mL of the supernatant were extracted. In addition, correlation between the concentrations in the plasmatic free fraction and in oral fluid was also evaluated. Plasmatic proteins were eliminated by filtering 0.5 mL of plasma samples using Microcon filter devices Ultracel YM-3 (Millipore Corp., Billerica, MA, USA). 

In the laboratory, aerosol samples were individually cut from the filter-tape roll and extracted on a 47-mm filter holder (Millipore) with 200 mL of distilled deionized water maintained at 50-60 °C. The leachates were analyzed for sodium content by flame atomic absorption with a Perkin-Elmer Model 373 spectrophotometer. The soluble sodium was assumed to be derived only from sea salt. Estimates of total sea salt in each sample were obtained by multiplying the sodium value by 3.25, which is the salinity-to-sodium ratio in bulk seawater (12). The sodium content of the 5-cm diameter, glass-fiber filter blanks averaged 18 /xg 12% (20 samples). Based on an average sample volume of 27 m, the background salt level produced by the sodium blank in each filter would be equivalent to 2.2 /xg/m. ... 

Flow times of polymer solutions were measured using a Ubbelohde capillary viscometer. Relative viscosity (j]x) was obtained from the ratio of the flow times of a solution and the solvent. Before each measurement, a solution in the viscometer was sealed and allowed to equilibrate with a thermostatted water tank for at least 20 min. The temperature fluctuation of the water tank was smaller than 0.1 °C. All samples used for flow time measurements were clarified by filtration through Millipore 0.45 xm PTFE filters. Each polymer solution was measured for three times so that the relative error was less than 0.2 %. 

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