Environmental applications of a cryptand adjustable-capacity anion-exchange separator

Thermodynamics of complexation of aqueous 18-crown-6 with potassium ion: apparent molar volumes and apparent molar heat capacities of aqueous 18-crown-6 and of the (18-crown-6+potassium chloride) complex at temperatures (278.15 to 393.15) K, at molalities (0.02 to 0.3) mol·kg−1, and at the pressure 0.35 MPa

“…The calculation of C p,/ (18C6: K + ,Cl À ) was carried out iteratively by adjusting c i of equation (2) for (18C6: K + ,Cl À ). Values of C p,/ (18C6) were obtained from equation (2) and the parameters in table 4 and values of C p,/ (KCl) were obtained from the analysis of Sorenson and Woolley [36]. Values of C p,/,t were obtained from equation (6),…”

“…Values of C p,/ (18C6: K + ,Cl À ) determined through application of YoungÕs Rule are shown in figure 3 along with the regression surface to those values, which are obtained with equation (2) and parameters given in table 4. Values of m eq (18C6: K + ,Cl À ) at a given m decrease with increasing T because log Q decreases with increasing T. We found no values in the literature for C p,/ (18C6: K + ,Cl À ).…”

“…Because of their selective complexation abilities, macrocycles have been used extensively in applications involving cation transport, separation, and detection. Macrocycles have been used as phase transfer catalysts in chemical syntheses, as stationary phases [2], and as mobile phase additives [3] to improve separations in ion chromatography. Many macrocycles have been synthesized with the aim of their incorporation into ion-selective sensors [4], liquid membrane systems [5], and solvent extraction systems [6].…”

Novel ion chromatographic stationary phases for the analysis of complex matrices

“…For example, Woodruff et al have utilised hydroxide gradients, varying both hydroxide concentration and the nature of the subsequent metal ion (LiOH, NaOH and KOH), to control column capacity in order to initially retain, and then rapidly elute, large concentrations of matrix anions. [31][32][33] Woodruff et al applied this technique to the determination of trace anions in 2% sulfuric acid, 31 the simultaneous determination of inorganic, organic and polarisable anions in industrial wastewater, 32 and the determination of chloride and sulfate in semi-conductor-grade etchants, comprised of acetic acid, nitric acid and phosphoric acid. 33 Fig.…”

Capillary ion chromatography

“…As such, stationary phases that are expensive to prepare, are more easily used in the capillary format. Kryptand-based stationary phases that have been introduced for variable capacity gradients [34,35] can, for example, profit from a capillary column adaptation. Further, the consumption of eluent and sample solutions is decreased and this becomes invaluable when samples are of the order of lL or sub-lL and cannot easily be analyzed by conventional scale LC or IC.…”