Soluble fractions, measurement

Sol-Gel Measurements. The relative rates of crosslinking and scission may be estimated from soluble-fraction measurements. For an initial random molecular weight distribution and random chain scission, extrapolating a curve of S + S vs. 1/D, where S = sol fraction and D —... 

Fig. 1. The I raciion, /, of protons having long TS relaxation times, and soluble fractions,. V, in irradiated PDMS as a function of corrected radiation dose. The gel do.ses, Tj., were determined experimentally, while the effective radiation dose. i. . was 60kGy and OkGy for NMR and soluble fraction measurements, respectively. Reproduced from ref. 77 with...

Fig. 1. Promotion of ethylene synthesis by MG pericarp discs following treatment with water or varying concentrations (uronic acid equivalents) of B fruit water soluble fraction. Bars indicate SEs for the means of measurements of sets of 8 discs/teatment fr wt, Fresh weight.

On-line and off-line measurements are often grouped and considered as permanent or continuous measurements, when results are given with a more or less regular time interval. Taking into account the complexity of some wastewaters (mainly industrial), it is thus quite impossible to carry out perfect sampling for a complete representation of the medium. But if we assume that emerging pollutants are mainly present in the soluble fraction of wastewater, the only re-... 

The enzyme proteins were found only in the soluble fraction of disintegrated liver (G10). However, measurable activities of both the enzymes have also been described for isolated cell nuclei (S14, S15). 

Figure 12. Possible isotope fractionation steps during anaerobic photosynthetic Fe(II) oxidation (APIO). It is assumed that the process of oxidation proceeds through an oxidation step, where Fe(II),q is converted to soluble Fe(III) in close proximity to the cell, followed by precipitation as ferric oxides/hydroxides. As in DIR (Fig. 5), the most likely step in which the measured Fe isotope fractionations are envisioned to occur is during oxidation, where isotopic exchange is postulated to occur between pools of Fe(II) and Fe(III) (Aj). As discussed in the text and in Croal et al. (2004), however, it is also possible that significant Fe isotope fractionation occurs between Fe(III), and the ferrihydrite precipitate (Aj) in this case the overall isotopic fractionation measured between Fe(II), and the ferrihydrite precipitate would reflect the sum of A and Aj, assuming the proportion of Fe(III) is small (see text for discussion). Isotopic exchange may also occur between Fe(II),q and the ferric hydroxide precipitate (Aj), although this is considered unlikely.

With regard to the results of our infrared study, a word of caution is appropriate. The large decreases in the concentration of the aliphatic bridges after oxidation, as measured by transalkylation (Table III), cannot be expected to match those indicated in the difference infrared spectra between oxidized and fresh coals. This is because the spectra measure the total aliphatic content of the samples, namely aliphatic bridges, hydroaromatics, and aliphatic side chains. In contrast, results in Table II show differences in relative concentrations of the aliphatic bridges, which represent only a part of the total aliphatics. Furthermore, concentrations measured by transalkylation correspond to only the soluble fractions of the reaction products some of the more complex transalkylation products may be retained in the residue itself. 

The GPC technique was used to determine gel formation. Figure 13 shows the soluble fraction of aromatic polysulfone I measured with this technique after irradiation at 30 and 150°C. The relative radiation resistance of different polymers can be obtained by comparison of the gel doses (the highest dose for complete solubility of the polymer) provided that the initial molar masses of the of the polymers are known, or from G(S) and G (X) values these can be derived from the dose dependence of the soluble fractions beyond the gel dose, using a Charlesby-Pinner, or Saito-type plot with allowance for the molar mass distribution. 

The soluble fraction for a given incident dose can be determined from Figure 2 provided that (l) all the soluble fraction was removed from the film during the development step, and (2) there was no volume contraction due to gel formation upon irradiation. If soluble material remained in the film, the measured soluble fraction will be systematically lower than the actual value. However, a volume contraction would result in a systematically higher than actual value for the soluble fraction. 

To investigate further the chemical characteristics of potential alternative emulsifiers, the water-soluble fractions (WSFs) of each emulsifier were measured [61]. The samples were analyzed for total recovered hydrocarbons (TRH) in the C10-C36 region and PAHs [3, 62]. The chemical analysis of the emulsifier WSFs did not detect PAHs. Consequently, in the future, use of low-fluorescence emulsifiers in the reformulated Syndrill 80 20 (Mod) will allow the measurement of biliary fluorescence as a biomarker of exposure in field-caught fish attracted to cutting piles, with any detected fluorescence eliminating the drilling mud Syndrill 80 20 (Mod) as a source of fluorescent metabolites in the biliary secretions. 

One part of commercial defatted soy flakes was extracted with ten parts of dilute NaOH (pH 9-10). After removal of spent flakes, the total extract was adjusted to pH 4.5 with dilute HCl to precipitate the curd. The curd was washed three times with H2O, resuspended at pH 7.0, and freeze dried. Intrinsic viscosity, optical rotation, and differential scanning calorimetry (DSC) measurements show the soluble fraction of curd to be native. 

Alkaline hydrolysis of cockroach residues subsequent to extraction under nitrogen with 80% ethanol yielded methionine and methionine sulfoxide in a ratio of 10 to 1. Additional evidence for the presence of combined methionine sulfoxide was obtained by measuring the amount of methionine sulfoxide-S35 in acid and enzymatic hydrolyzates after assimilation of Na2S3504. The data are believed to be indicative of naturally occurring peptide- or polysaccharide -bound methionine sulfoxide. Other combined amino acids were determined by ion exchange chromatography of the 5% trichloroacetic acid-insoluble cockroach residues after hydrolysis with acid or alkali. /3-Alanine, normally present only in the soluble fraction of an organism, was found in the insoluble, proteinaceous residue. 

For our purposes, the characterization of the glycerophosphocholine present in the water-rich phase will have center stage, with a more modest discussion of the fatty acid ester fraction. As a footnote to the above experiment, one should measure carefully the distribution of phosphorus in the two fractions the phosphorus should be exclusively in the water-soluble fraction. 

---