a new sensitive and selective spectrophotometric method for the determination of iron using a pvc membrane containing bathophenanthroline and dioctylphethalate as the solid phase extraction medium is investigated. fe(ii) in an aqueous sample solution is trapped on the membrane with an anion species, picrate ion and forms a complex with bathophenanthroline. the absorbance of the red-orange membr...

We present a short overview over recent MD simulations of systems of fully flexible polyelectrolyte chains with explicitly treated counter ions using the full Coulomb potential. The main emphasis is given on the conformational properties of the polymers, with a short discussion on counter ion condensation.

Gloeobacter rhodopsin (GR) is a eubacterial proton pump having a highly conserved histidine near the retinal Schiff base counter-ion, aspartate. Various interactions between His and Asp of the eubacterial proton pump have been reported. Here, we showed the pH-dependent trimer/monomer transition of GR in the presence of dodecyl-β-D-maltoside by size-exclusion chromatography. The pH dependence wa...

The bulk and interfacial transport properties of PANI free-standing membranes have been investigated in acidic media with chloride as common counter-ion and with di€erent co-ions, using the a.c. impedance technique with a four-electrode cell. The experimental data were compared to a recently proposed theoretical expression, based on use of the Nernst±Planck equation for mass transport and on sl...

The role of counter ions and ion dissociation in establishing the equilibrium swelling of balanced and unbalanced polyampholytic hydrogels has been investigated experimentally and theoretically. The swelling dependence on both the net charge offset and the external bath salt concentration has been examined using an acrylamide based polyampholytic hydrogels. By careful consideration of the swell...

The ammonium counter ion is shown to influence the morphology, physicochemical properties and electrochemical performance of hydrothermal carbon.