Electrochemical determination of the stability of complexes formed by proton-ionizable ligands of 3,5-disubstituted 1H-pyrazole with phenethylamine.
The application of two extreme models for diffusion in two-component systems to electrochemically determine equilibrium constants is discussed. The application of cyclic voltammetric, diferential pulse and rotating-disc electrode voltammetric data to elucidate the stoichiometry and formation constant of complex species by applying a generalization of the molar-ratio method is described. Molar-ratio experiments permit the distinction between the limiting diffusive regimes. The values of the equilibrium stability constants for complexation of phenethylamine and phenethylammonium ions by a 26-membered dioxotetraester crown of 3,5-disubstituted 1H-pyrazole as free ligand 1[L] and as dipyrazolate anion 1'[L(2-)]2Na(+), respectively, were determined.
Characterization of inclusion complexes of organic ions with hydrophilic hosts by ion transfer voltammetry with solvent polymeric membranes.
The quantitative characterization of inclusion complexes formed in aqueous phase between organic ions and hydrophilic hosts by ion-transfer voltammetry with solvent polymeric membrane ion sensors is studied, both in a theoretical and experimental way. Simple analytical solutions are presented for the determination of the binding constant of the complex from the variation with the host concentration of the electrochemical signal. These solutions are valid for any voltammetric technique and for solvent polymeric membrane ion sensors comprising one polarisable interface (1PI) and also, for the first time, two polarisable interfaces (2PIs). Suitable experimental conditions and data analysis procedures are discussed and applied to the study of the interactions of a common ionic liquid cation (1-octyl-3-metyl-imidazolium) and an ionisable drug (clomipramine) with two hydrophilic cyclodextrins: α-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin. The experimental study is performed via square wave voltammetry with 2PIs and 1PI solvent polymeric membranes and in both cases the electrochemical experiments enable the detection of inclusion complexes and the determination of the corresponding binding constant.
Perceived job importance and job performance satisfaction of selected clinical nutrition management responsibilities.
A nationwide survey of clinical nutrition managers was conducted to assess perceived importance of selected job responsibilities and perceived performance satisfaction of those job responsibilities. A questionnaire was developed to achieve the study objectives, validated by an expert panel, and pilot-tested prior to data collection. All members of the American Dietetic Association's Clinical Nutrition Management dietetic practice group (N=1,668) were asked to rate the importance of selected job responsibilities and their satisfaction with those responsibilities using Likert-type scales with descriptions. Results revealed that clinical nutrition managers perceived all job responsibilities listed in the questionnaire to be important (ie, the mean score of each responsibility was >3.0 of a 4.0 scale). Respondents rated regulatory-related job responsibilities as most important and were most satisfied with their performance of these responsibilities. Following regulatory-related responsibilities, clinical nutrition managers perceived patient satisfaction and staff retention to be more important than other responsibilities. In general, clinical nutrition managers were more satisfied with their job performance for job responsibilities that they ranked as more important.