Concentration shifts

Table 4. Effect of specific surface area of filler and its concentration on concentration shift factors aci and ac for composites copolymer + ash (the reference concentration 10%)...

Sulfides with widely different solubilities and solubility products can be selectively precipitated by adding S2 ions to the solution removed from the chlorides in the first step (see Fig. 11.20). Some metal sulfides (such as CuS, HgS, and Sb2S3) have extremely small solubility products and precipitate if there is the merest trace of S2" ions in the solution. Such a very low concentration of S2 ions is achieved by adding hydrogen sulfide, H2S, to an acidified solution. A higher hydronium ion concentration shifts the equilibrium... 

Normalization is, in practice, also useful to counteract any possible fluctuations in the sample concentration. These fluctuations are, in practice, mostly due to sample temperature fluctuations, and to instabilities of the sampling system and they may lead to variations of the dilution factor of the sample with the carrier gas. Of course, normalization is of limited efficiency because the mentioned assumptions strictly hold for simple gases and they fail when mixtures of compounds are measured. Furthermore, it has to be considered that in complex mixtures, temperature fluctuations do not result in a general concentration shift, but since individual compounds have different boiling temperatures, each component of a mixture changes differently so that both quantitative (concentration shift) and qualitative (pattern distortion) variations take place. 

A number of animal studies have revealed extrapulmonaiy effects. Again, there is some question as to which of these may represent an effect of ozone, or a direct ozone-induced intermediate, rather than a more indirect response to pulmonary toxicity, perhaps mediated by neurohumoral factors. Thus, for instance, the observations of altered hepatic nucleic acid concentrations, shifts in the content of metals in the liver, alterations in urinary pH, increases in liver weight and alkaline phosphatase... 

Figure 10.17 H NMR spectra of spent acid samples spanning operational range of sulfuric acid concentrations. Shift of sulfuric acid peak with change in acid strength is indicated. Acid soluble oils and micellar water are readily quantified.

NH3(g). An increase in the N2 or H2 concentration or a decrease in the NH3 concentration shifts the equilibrium from left to right. A decrease in the N2 or H2 concentration or an increase in the NH3 concentration shifts the equilibrium from right to left. 

Ballpark Check In the NH3-NH4CI solution, NH4+ is the common ion, and raising its concentration shifts the equilibrium for the principal reaction to the left. 

This enables you to create a gradient that is almost linear. If the volume to the inlet line is not considered, then a larger amount of methanol will be added to a smaller amount of water and the concentration shift will bias the resulting elutions. 

The first systematic study of Zn shieldings by high-resolution pulse FT methods is that by Epperlein et al. (242) The non-linearity of the shift dependence on concentration for a variety of zinc salts is taken as evidence for complexation with the counter-ion through displacement of water molecules from the hexacoordinated hydration sphere. Generally the concentration shifts for the halides follow the order Cl > Br > I whereas nitrate, perchlorate, and sulphate do not show any concentration dependence. 

The mean outer radius decreases as the lipid concentration is lowered, but the magnitude of the shift is very small over a wide range of concentrations. A millionfold change in concentration shifts the peak by only a few Angstrom units. 

The conventional inverse gas chromatography (IGC) is based on equations that assume equilibrium is established during the course o the chromatograph. Consequently, those stationary phases that exhibit marked hysteresis in sorption/desorption give IGC sorption data at considerable variance with long-term gravimetric methods. A modified frontal procedure was developed that avoids the assumption of equilibrium to enable studies of interaction kinetics of gas phase components with a stationary phase, such as a biopolymer, having entropic as well as enthalpic relations affected by concentration shifts and time dependent parameters. 

Type and concentration of organic solvent (organic modifier). Increasing concentrations shift the equilibrium away from the surface. 

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