Ion pair dispersive liquid- liquid microextraction (IP-DLLME) method combined with flame atomic absorption spectrometry was proposed for the determination of trace amounts of copper(II). By using pyrocatechol violet as chelating agent and cetyltrimethyl ammonium bromide as an ion pairing agent, the trace amount of copper(II) was extracted in chloroform. The factors influencing the formation cop...

Complexes of benzo-15-crown-5 macrocycle with Li+ and Cs+ ions were investigated by 7Li and 133Cs NMr in a number of nonoqueous solutions. The resulting 1:1 complex with Li+ ion was found to be much more stable than that with Cs+ ion. With the exception of pyridine solutions the stabilities of the complexes varied inversely w...

The acidity constants of some amino acids (Am) were determined by potentiometric pH titration. The stability constants of the 1:1 complexes formed between M2+: Ca2+, Mg2+, Mn2+, Co2+, Ni2+, Cu2+ or Zn2+ and Am2-, were determined by potentiometric pH titration in aqueous solution (I = 0.1 M, NaNO3, 25°C). The order of the stability constants was reported. It is shown that the stability of the bi...

a simple and sensitive extraction-spectrophotometric method for rapid and accurate determination of benzocaine in pure and dosage forms was developed. benzocaine was effectively extracted as a 1:1 ion pair complex with dicyclohexyl-18-crown-6 and calmagite in acidic media into chloroform, followed by spectrophotometric determination at 486 nm. molar absorptivity of the ternary complex at this w...

The technique used previously to observe complex formation between bacitracin, Mg++, and Ca5-isoprenyl pyrophosphate has been employed to measure association constants. The constant for the bacitracin A, Mg++, C55-isoprenyl pyrophosphate complex was lo6 M-I. The binding constants for other bacitracin peptides were lower and correlated with their antibiotic activities. &farnesyl pyrophosphate al...

The acidity constants of some amino acids (Am) were determined by potentiometric pH titration. The stability constants of the 1:1 complexes formed between M2+: Ca2+, Mg2+, Mn2+, Co2+, Ni2+, Cu2+ or Zn2+ and Am2-, were determined by potentiometric pH titration in aqueous solution (I = 0.1 M, NaNO3, 25°C). The order of the stability constants was reported. It is shown that the stability of the bi...

The present work reported density, viscosity, speed of sound, electrical conductivity and refractive index data of L-alanine in the aqueous solutions of 1-hexyl-3-methylimidazolium ibuprofenate at T= 298.15 K. Using the measured data, partial molar volume of transfer ( ), partial molar isentropic compressibility of transfer ( ), viscosity B-coefficient of transfer (∆traB), ion association const...

The interaction of Fe2+ ion with Pyrazole was theoretically studied by Gussian 03, software at HF/(LanL2DZ+6-31G) and HF/ (LanL2DZ+6-31G (d)) levels in gas phase and solution. In this study acompartion between optimized structures of Pyrazole molecule in aspect of thermodynamicparameters such as enthalpy (H°), Gibbs free energy (G°) and entropy (S°) in presence of metallic ion(Fe2+), was perfor...