Anion concentration, dependence

The anomalous features are observed on well-ordered (111) surfaces in a variety of electrolytes over a wide range of pH (0-11), but the potentials at which the features appear and the detailed shapes of the I-V curves vary considerably. Specifically, the potential region (versus RHE) in which the features appear changes with anion concentration in sulphate and chloride electrolytes, but not in fluoride, perchlorate, bicarbonate or hydroxide electrolyte. In sulfate electrolyte, at constant anion concentration the region shifts (versus RHE) with varying pH, while in fluoride, perchlorate, bicarbonate and hydroxide electrolyte it does not. The use of UHV surface analytical techniques has established to a reasonable (but not definitive) extent that adventitious impurities are not involved in the anomalous process, i.e., the only species participating in the chemistry are protons/hydroxyIs, water and the anions of the solute. On the basis of the pH and anion concentration dependencies, I agree with the... 

Dietz, M. L., Stepinski, D. C. (2008). Anion concentration-dependent partitioning mechanism in the extraction of uranium into room-temperature ionic liquids. Talanta, 75, 598-603. 

Dietz, ML. Stepinski, D.C., (2008). Anion Concentration-Dependent Partitioning Mechanism in the Extraction of Uranium into Room-Temperature Ionic Liquids. Talanta, Vol.75, pp. 598-603... 

The distribution of highly extractable solutes such as and Pu between the aqueous and organic phases is strongly dependent upon the nitrate anion concentration in the aqueous phase. This salting effect permits extraction or reextraction (stripping) of the solute by controlling the nitric acid concentration in the aqueous phase. The distribution coefficient, D, of the solute is expressed as... 

For both film-free and film-forming conditions a decrease in corrosion rate is observed as the concentration of the anion increases. For some anions the maximum in the corrosion rate may be attained at low concentrations depending on the species and concentration (Fig. 2.2). One form of inhibition... 

For many metals and alloys the determination of /p is complex, and its magnitude is governed by many factors such as surface finish, rate of formation, alloying constituents, and the presence of those anions, such as halides, that promote localised breakdown. In many instances the attack on passive films by halide ions shows a temperature and concentration dependence similar to the effect of hydrogen ions, i.e. the rate of film dissolution increases with concentration in accordance with a Freundlich adsorption relationship... 

The relative importance of these functions also depends to a considerable extent on the solution conditions. Under favourable conditions of pH, oxidising power and aggressive anion concentration in the solution, Function 1 is probably effective in preventing film breakdown. Under unfavourable conditions for inhibition, localised breakdown will occur at weak points in the oxide film, and Functions 2 and 3 become important in repairing the oxide film. 

Superoxide anion scavenging activity of the enzymatically synthesized poly(catechin) was evaluated. Poly(catechin), synthesized by HRP catalyst, greatly scavenged superoxide anion in a concentration-dependent manner, and almost completely scavenged at 200 p.M of a catechin unit concentration. The laccase-catalyzed synthesized poly(catechin) also showed excellent antioxidant property. Catechin showed pro-oxidant property in concentrations lower than 300 jlM. These results demonstrated that the enzymatically synthesized poly(catechin) possessed much higher potential for superoxide anion scavenging, compared with intact catechin. 

Figure 16(a) (O) shows the EMF responses of a 1,2-dichloroethane membrane containing anionic sites (KT/ C1PB). A Nernstian response was obtained. An SHG response to KCl was observed at activities of the latter above 10 M [Fig. 16(b), O]-These results can be interpreted in the same way as for ionophore-incorporated PVC liquid membranes, for which we have shown that the concentration of oriented cation complexes at the liquid-liquid interface can explain both the observed SHG signal and EMF response. The present SHG responses thus suggest primary ion concentration dependent charge separation at the interface of the 1,2-dichloroethane membranes incorporated with ionic sites. 

No new absorption bands are observed in other cases, largely due to the fact that the strong absorptions of the aromatic donors obstruct the UV-spectral measurements. For the complex between CBr4 and TMPD, the quantitative analyses of the temperature and concentration-dependent absorptions of the new band at 380 nm afford the extinction coefficient of ct = 3.2 x 103 M 1 cm x, as well as the thermodynamic parameters for complex formation AH = - 4.5 kcalM x, AS = - 14 e.u., and Kda = 0.3 M x at 295 K. Such thermodynamic characteristics are similar to those of the dihalogen complexes of as well as those of other acceptors with aromatic donors. Similar results are also obtained for CBr4 associates with halide and thio-cyanide anions [5,53]. 

Anion concentrations can also be monitored through lanthanide luminescence. Once again, a wide range of pathways can be responsible for luminescence quenching. For instance, complex (60) with a pendant phenanthridinium group exhibits halide ion-dependent luminescence properties as a result of collisional quenching of the phenanthridinium-centered singlet state by halide ions.165... 

Sulfur dissolves in liquid ammonia to give intensely coloured solutions. The colour is concentration-dependent and the solutions are photosensitive. Several S-N anions are present in such solutions.76,77 The primary reduction products are polysulfides Sx2, which dissociate to polysulfur radical anions, notably the deep blue S3 ion. In a 1M solution, the major S-N anion is cyc/0-[S7N] with smaller amounts of 21 and a trace of 20.76... 

Pulmonary macrophages cultured in vitro for 20 h with media containing 14.5-58.0 mg Ni/kg as nickel chloride Concentration-dependent decrease in viability of alveolar macrophages highest dose had survival of <50%. Death associated with release of superoxide anions 11... 

Derive the polynomial expressions for the concentration dependence of electrons, metal vacancies, and anion vacancies for a compound MX showing Schottky equilibrium (Section 7.9.4). Insert values of the equilibrium constants to obtain polynomial expressions for the cases where electronic defects dominate. 

C5-derived peptide in serum. This molecule lacks anaphylatoxin activity (i.e. it cannot cause smooth muscle contraction), and its ability to cause che-motaxis in neutrophils is about 10-20 times lower than that of C5a. However, human serum also contains a heat-stable, anionic protein termed co-chemotaxin (relative molecular mass = 60 kDa), which acts in a concentration-dependent manner to permit C5a des Arg to act as a chemoattractant for neutrophils. Thus, C5a des Arg plus cochemotaxin working together probably account for most of the neutrophil chemoattractant activity in vivo following complement activation. The mechanism of action of cochemotaxin is unknown, but it may form a physical complex by attaching to a sialic acid residue on the oligosaccharide chain of C5a des Arg. Deglycosylation of C5a des Arg increases its chemoattractant activity more than 10-fold, and its dependency upon cochemotaxin is decreased. 

Figure 2. Dependence of pH on total anion concentration ((%) infinite dilution (O) NaCl ( ) NatSO (A) sodium citrate (V) mixed solution)...

As shown in figure 4, titration with HC1 or absorption of SO2 as bisulfite results in a different dependence of pH on fraction neutralization because the total anion concentration is increased. The slope of pH versus f is typically greater than... 

This systematic error affects the usefulness of these series in determining the constant a, but they still provide valuable data for use in determining dependence of the equilibrium on temperature, fraction neutralization, and total anion concentration. 

The dependence on fraction neutralization and total anion concentration should reflect the extent to which the bisulfite activity is not proportional to total dissolved SO2. As expected, the dependence on f is quite small, since dissolved SO2 is present primarily as bisulfite at pH 3.5 to 5.0. The effect of anion concentration is in the direction expected since bisulfite activity would be reduced by ion pairing in more concentrated solutions. 

Composition dependence of pH and Ps02 H20 can be represented as a function of fraction neutralization and total anion concentration. 

Fig. 4.3 The dependence of the pseudo first-order rate constants upon anion concentration for the anation of Co(tmpyp)(H20) + by SCN at 15, 25, and 35°C in 0.1 M H +, p = 1.0 M." The solid lines conform to Eqn. (4.22). Reproduced with permission from K. R. Ashley, M. Berggren and M. Cheng, J. Amer. Chem. Soc. 97, 1422 (1975) (1975) American Chemical Society.

Several workers have concluded that under conditions used in their study ion-pairing in the mobile phase between amphiphilic hetaeron ions and oppositely charged sample components governed retention. Horvath et al. (34) examined the effect of alkyl sulfates and other alkyl anions on the retention of catecholamines in which both the concentration and the length of the alkyl chains of the hetaerons were varied. The hyperbolic concentration dependence of the retention factor shown in Fig. 48, was found to be similar to that reported by others. 

A systematic carbocation concentration dependency study on NMR chemical shifts was performed for the C-l-protonated 477-cyclopenta[fi e/ phenanthrenium cation 7H+ and the C-l-protonated pyrenium cation 2H+ (Fig. 11). Shielding of the PAH arenium ion protons and carbons was observed with decreasing FSO3H PAH ratios without noticeable line-broadening. This was attributed to cation-anion interactions in the low FSO3H PAH domain and possible formation of contact ion... 

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