Polyethylene glycol, determination

Stratifying water systems for selective extraction of thiocyanate complexes of platinum metals have been proposed. The extraction degree of mthenium(III) by ethyl and isopropyl alcohols, acetone, polyethylene glycol in optimum conditions amounts to 95-100%. By the help of electronic methods, IR-spectroscopy, equilibrium shift the extractive mechanism has been proposed and stmctures of extractable compounds, which contain single anddouble-chai-ged acidocomplexes [Rh(SCN)J-, [Ru(SCN)J, [Ru(SCN)J -have been determined. Constants of extraction for associates investigated have been calculated. 

Chaput, Jeminet and Juillard measured the association constants of several simple polyethylene glycols with Na", K", Cs", and Tl". Phase transfer catalytic processes and most biological processes are more likely to involve the first two cations rather than the latter two, so we will confine the discussion to these. Stability constants for the dimethyl ethers of tetra-, penta-, hexa-, and heptaethylene glycols were determined poten-tiometrically in anhydrous methanol solution and are shown in Table 7.1. In the third column of the table, the ratio of binding constants (Ks/K s) is calculated. Note that Simon and his coworkers have referred to this ratio as the selectivity constant. ... 

IR analysis can also be used quantitatively to determine the EO-PO ratio [12]. Using mixtures of polyethylene glycol and polypropyene glycol as calibration standards, the ratio of two absorbances, one due to the methyl group of the PO unit (e.g., the C-H stretch band at 2975 cm ) and one due to the methylene group (e.g., the C-H stretch band at 2870 cm ), are plotted against percent of PO content. The ratio of the same two absorbances taken from the IR spectrum of a poloxamer may then be used to determine its percent of PO content by interpolation. 

Kuokkanen (1985) determined complexation constants for 4-tert-butyl- and 4-chlorobenzenediazonium tetrafluoroborate with polyethylene glycols of average molecular mass 300, 600, 1000, and 2000 under the same experimental conditions as mentioned above. The constants are significantly lower than those with... 

In our ongoing efforts to develop oxidation catalysts that are functional in water as environmentally berrign solvent, we synthesized a water-soluble pentadentate salen ligand with polyethylene glycol side chairts (8). After coordination of copper(II) ions to the salen ligand, a dinuclear copper(II) complex is obtained that is soluble in water, methanol and mixtures of both solvents. The aerobic oxidation of 3,5-di-tert.-butylcatechol (DTBC) into 3,5-di-terr.-butylqitinone (DTBQ) was used as a model reaction to determine the catalytically active species and initial data on its catalytic activity in 80% methanol. 

In the previously described electrophoretic methods, the capillary was filled with electrolytes only. Another mode of operation in capillary electrophoresis involves filling the capillary with gel or viscous polymer solutions. If desired, a column can be packed with particles and equipped with a frit.68 This mode of analysis has been favorably used for the size determination of biologically important polymers, such as DNA, proteins, and polysaccharides. The most frequently used polymers in capillary gel electrophoresis are cross-linked or linear polyacrylamide,69 cellulose derivatives,70-75 agarose,76 78 and polyethylene glycols. 

The responses of the test seed to increased external osmolarity were determined by germinating the seeds in a polyethylene glycol (PEG) solution of 40.3 mOsm (10). The only test seeds significantly affected by this treatment were those of tomato where PEG-treated seed germination was 69.3% of that observed in deionized water. Dilution of the aqueous extract to 1 32 (w/w) removed all inhibitory action, but the diluted solution increased wheat germination. 

Grelier etal. (1997) synthesized a variety of UV stabilizers based upon hydroxy-phenylbenzotriazoles incorporating an isocyanate functionality. These were reacted with wood using microwave energy. The modified woods were exposed to UV irradiation and the photoinduced discolouration determined. It was found that the best protection was obtained when the UV stabilizer was used in conjunction with polyethylene glycol, or hindered amine light stabilizers. 

The application of thermomorphic solvent systems as a new recycUng concept was investigated in various C - C bond-forming reactions. Therefore methods for a systematic choice of solvent combinations were developed. In addition to common organic solvents more unusual solvents Hke cycHc carbonates, pyrroUdones, polyethylene glycols and lactones were used in the investigations. The phase behaviour of the new solvent systems was determined by cloud titrations. From these experiments information about the temperature dependency and an appropriate composition for the reactions could be obtained. The results were used in the development of an expert system for the solvent selection. 

Acute toxicity of bromethalin. Acute LD5QS were determined in various target and non-target species by gavage administration of bromethalin solublized in polyethylene-glycol 200. These data... 

Total ethanol may be determined by gas chromatography using a Stabilwax (polyethylene glycol) column with helium carrier gas under isothermal (35°C) conditions [8], Analyte detection is performed using with a flame ionization detector [8]. The level of ethanol is typically 6 % w/w. 

Ballantyne et al. examined the ocular effects of CS in polyethylene glycol-CPEG) solutions, as a powder, and as smokes. Test solutions were made up in concentrations of 0.5, 1, 2, 5, and 10Z CS in PEG. Each was tested on 10 rabbits with 0.1-ml drops instilled into one eye. Four groups of 20 rabbits were tested at 0.5, 1, 2, and 5 mg of CS as a powder. Ten rabbits were exposed to CS grenade smoke for 15 min the average CS concentration was 6 g/m3. The effects of the hydrolysis products of CS were also examined. Ten animals were tested with o-chlorobenzaldehyde and 10 with malono-nitrile. The amounts of the two compounds were determined as the ratio obtained by the hydrolysis of a 5Z solution of CS. This was a... 

The bioadhesive characteristics of tablets for oral use made from modified starch, poly(acrylic acid), polyethylene glycol) and sodium carboxymethyl cellulose were recently investigated [406]. In this work, the force and energy adhesion were determined in vitro, and maximum adhesion times were evaluated in vivo in humans [406], In the in vitro, studies, the poly(acrylic add) gave the best performance, however in vivo bioadhesion was not strongly correletated with... 

Note Soluble recombinant interleukin-2 (IL-2) was modified with various lengths of polyethylene glycol (PEG) polymers with average molecular weight listed. The final PEG to IL-2 ratio is listed as molar ratio, and their respective hydrodynamic size was determined based on their sendimentation coefficient. Hence the molecular weight listed in Effective Size is not the sum of the PEG and IL-2 with consideration of molar ratio of the PEG-IL-2 conjugates. 

---