Surfactant-dye interactions are very important in chemical and dyeing processes. The dyes interact strongly with surfactant and show new spectrophotometric properties, so the UV-vis absorption spectrophotometric method has been used to study this process and extract some thermodynamic parameters. In this work, the association equilibrium between ionic dyes and ionic surfactant were studied by a...

Specific ion effects are ubiquitous in biological and colloidal systems. The addition of electrolytes to ionic surfactant solutions has pronounced effects on micellar properties, such as critical micelle concentration (cmc), micellar size, and shape. Ions play an important role in colloid stability and aggregation behavior of ionic surfactant solutions. Despite extensive experimental data, ther...

using the mixed solvents, (water +ethanol + propanol), the solubility of cdf2 was determined byevaporating method at 25° c. the results showed that the sollbility, s, of cdf2 decreases bydecreasing the dielectric constant of the mixed solvent .once the solubility of cdf2 was determined,the concentration solubility product, ksp(c)=4s3, was calculated .furthermore ,by estimating the meanactivity ...

in the present study, a simple and sensitive extractive spectrophotometric method is described for determination of buspirone. the method is based on the reaction of buspirone and bromocresol green. the ion-pair complex was quantitatively extracted into chloroform at ph 2.3 followed by spectrophotometric determination at 415 nm. the complex was stable up to 2 days and obeyed beer's law over the...

a simple and sensitive extractive spectrophotometric method is described for determination of tropicamide. the method is based on the reaction of tropicamide and bromocresol green. the ion-paired colored complex was extracted with chloroform at ph 3. the extracted complex showed maximum absorbance at 423 nm. the complex was stable up to 2 days and obeyed beer's law over the concentration r...

barrier to the permeation of most drugs, and especially as a hydrophobic barrier against hydrophilic drugs and ionized drugs. One possible means of facilitating the transdermal delivery of ionic drugs is through ion-pair formation. Oppositely charged ions can interact to form new species known as ion-pairs. This association reduces or neutralizes electrostatic charges and consequently reduces t...

using solvent evaporating and atomic emission spectrophotometric methods, the solubility of li2co3 in waterat 25°c was determined. comparing the value of thermodynamic solubility product constant, ksp(th),(ksp(tn) = exp(—ag.ss/rt)) of the mentioned salt to the value which is obtained from the observed solubility,shnoll-1 , and activity coefficients, f+ and f, which are estimated upon the extend...

This paper presents efflux time experiments performed in the absence and presence of aqueous solutions of Drag Reducing Agents (DRAs) when a liquid is emptied from a large open cylindrical storage tank through an exit piping system. The drag reducing agents studied are Dodecyl benzene sulfonate anionic surfactant and a mixed solution of surfactant and sodium chloride counter ion. The variab...

in this study a sensitive, simple and accurate spectrophotometric method was suggested for determination of tamsulosin in bulk powder and pharmaceutical dosage form based on the formation of an ion-pair complex between the drug and bromocresol green in a buffer solution at ph 3.5. the formed yellow color complex was extracted with chloroform and measured at 415 nm. the optimum reaction conditio...

Structural properties pertaining to the solvation of mixtures of dodecytrimethylammonium/dodecylsulfate adsorbed at water/air interfaces were studied using molecular dynamics techniques. Two different surfactant coverages, both in the submonolayer regime, were considered: an infinite-diluted catanionic pair and an equimolar mixture, at a surface concentration of 78.7 A2/headgroup. The most stab...