The Micellization and Clouding of Nonionic Surfactant,Poly(Ethylene Glycol) t-Octylphenyl Ether (Triton X-100): Effect of Halide Ions of (Sodium Salt) Electrolytes

In this investigation, the micellization and the clouding phenomena of a nonionic surfactant, poly(ethylene glycol) t-octylphenyl ether (Triton X-100) in the absence and presence of halide ions (sodium salt) electrolytes has been reported. The critical micelle concentration (CMC) of Triton X-100 (in the absence and presence of electrolytes) was measured by surface tension measurements. A decreasing trend of CMC was found with increasing the temperature as well as the concentration of electrolyte. The effectiveness of the halide ions was found in the order: F^? > Cl^? > Br^? > I^?. The surface properties of Triton X-100 were evaluated. The thermodynamic parameters of the micellar systems of Triton X-100 were evaluated and from these thermodynamics data, it was found that in the presence of electrolyte the stability of the micellar system is more. The cloud points (CPs) of Triton X-100 were also measured in the absence and presence of halide ions of electrolytes. With the addition of halide ions of sodium salt (electrolyte), a decrease in CP values was observed and the order was found to be: F^? > Cl^? > Br^? > I^?.     

Effect of (chloride salt) electrolytes on the mixed micellization of (equimolar) a cationic gemini (dimeric) surfactant and a cationic conventional (monomeric) surfactant

Herein we report the effect of (chloride salt) electrolytes on the mixed micellization of (equimolar) a cationic gemini (dimeric) surfactant, hexanediyl-1,6-bis(dimethylcetylammonium bromide) (16-6-16), and a cationic conventional (monomeric) surfactant, cetyltrimethylammonium bromide (CTAB) in aqueous solutions. In absence and presence of (chloride salt) MCl (where M?Li, Na, and K) electrolytes, the critical micelle concentration (CMC) of mixed (16-6-16 + CTAB) surfactants was measured by surface tension measurements. With increasing the concentration of electrolyte, the CMCs were increasing. The surface properties and the thermodynamic parameters of the mixed micellar systems were also evaluated. From these evaluated thermodynamic parameters, it was found that in presence of electrolyte the stability of the mixed micellar system is more.     

Study of the reaction methyl 4‐nitrobenzene‐sulfonate + Cl− in mixed hexadecyltrimethyl‐ammonium chloride‐triton X‐100 micellar solutions

The reaction methyl 4‐nitrobenzenesulfonate + Cl^? was studied in hexadecyltrimethylammonium chloride (CTAC) in the absence and presence of 0.1 M NaCl, as well as in mixed CTAC/Triton X‐100 (polyoxyethylene(9.5)octylphenyl ether) aqueous micellar solutions with CTAC molar fractions of 0.9, 0.8, 0.7, and 0.6. Conductivity measurements were used to obtain critical micellar concentrations and micellar ionization degrees of the various micellar reaction media. From these data, thermodynamic information on the cationic/nonionic mixed micellar solutions was obtained. Micellar effects on the observed rate constant were explained by pseudophase kinetic models. The estimated second‐order rate constants in the micellar pseudophase of the different micellar reaction media showed that pure CTAC and mixed CTAC/Triton X‐100 micelles, at the high cationic surfactant molar fractions studied, provide reaction sites of similar characteristics at the interfacial region. This was in agreement with previous structural studies carried out on mixed CTAC/Triton X‐100 micellar solutions. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 45–51, 2003     

Spectrophotometric study of thiocyanato complexation of cobalt(II) and nickel(II) ions in micellar solutions of a nonionic surfactant triton X-100

Complexation of cobalt(II) and nickel(II) with thiocyanate ions has been studied by precise spectrophotometry in aqueous and micellar solutions of a nonionic surfactant Triton X-100 of varying concentrations (20–100 mmol-dm^–3). With regard to cobalt(II), the formation of [Co(NCS)]⁺, [Co(NCS)₂], and [Co(NCS)₄]^2– was established. The formation constant of [Co(NCS)₄]^2–, is increased with increasing concentration of the surfactant, suggesting that the [Co(NCS)₄]^2– complex is formed in micelles. In contrast, the formation constants of [Co(NCS)]⁺ and [Co(NCS)₂] are remained practically unchanged. On the other hand, with nickel(II), the formation of sole [Ni(NCS)]⁺ and [Ni(NCS)₂] was established in both aqueous and micellar solutions examined, their formation constants being also remained unchanged. Interestingly, no higher complex was confirmed in the nickel(II) system, unlike cobalt(II). The unusual affinity of the [Co(NCS)₄]^2– complex with micelles will be discussed from thermodynamic and structural points of view.     

Effects of surface-active substances in square-wave voltammetry and potentiometric stripping analysis of amalgam-forming metal ions

The influence of surface active substances (SAS) (Triton X-100, sodium dodecyl sulfate and dodecyl pyridinium chloride (DPC)) on the potentiometric stripping analysis (PSA), square-wave voltammetry (SWV) and anodic stripping square-wave voltammetry (ASSWV) of Cd²⁺, Cu²⁺, Zn²⁺ and Bi(III) are measured for various contact times and detergent concentrations. Diagnostic criteria for the presence of SAS in electrolytes are reported. Zinc ions accumulate in the adsorbed layer of DPC, probably as a ZnCl⁺ complex. An anomalous dependence of zinc SWV peak currents on the delay time is observed.     

Surfactant effects on the spectrophotometry of the gadolinium—chrome azurols complex

Increased molar absorptivities and red-shifted absorbance maxima were noted only upon the addition of cetylpyridinium chloride (CPC), a cationic surfactant. A 1:2:4 gadolinium/chrome azurol S/CPC complex was forned but dissociated at [CPC]/ [Gd³⁺] > 4 apparently because gadolinim(III) was displaced from this complex by additional surfactant monomers. Ternary complexes having different stoichiometries formed in the presence of excess dye. Sodium dodecyl sulfate (SDS), an anionic suffactant, induced dissociation of the binary complex at micellar concentrations, suggesting that dissociation resulted from adsorption of Gd³⁺ cations on the negatively charged micellar surface. Addition of Triton X-100, a nonionic surfactant, had little effect at either micellar or submicellar concentrations. These results confirm that complex stability is an important factor in the use of surfactants as sensitizers in quantitative spectrophotometry.     

Determination of the Micellar Properties of Triton X-100 by Voltammetry Method

ABSTRACT

The diffusion coefficient of the micelle, the first CMC and the second CMC of Triton X-100 are determined by cyclic voltammetry without any probe. The first CMC and the second CMC of Triton X-100 are 3.1x lO^?1 and 1.3× 10^?1 respectively. The viscosity of the micelle solution, the micellar aggregation number and the micellar size increase but the diffusion coefficient decreases with Triton X-100 concentration increasing. The mechanism of the electrochemical reaction of Triton X-100 at platinum electrode is deduced by measurements of conductivity, pH and cyclic voltammetry.     

Effects of nonionic,cationic, and anionic micelles on the kinetics of the complexation reaction of nickel (II) with pyridine-2-azo-p-dimethylaniline

The stopped-flow technique has been used to study the effect of cationic (CTAN), nonionic (Triton X-100), andanionic (SDS) micelles on the rate of the reaction between nickel(II) ion and the ligand pyridine-2-azo-p-dimethylaniline (PADA) at 20.0°C and ionic strength 0.03 mol dm^?3. The complex formation reaction is markedly inhibited by both CTAN and Triton X-100 micelles. The kinetic dataare found to conform to a reaction mechanism which implies only partitioning of the ligand between water and the micellar phase, the estimated bindingconstant of PADA being significantly larger in the presence of CTAN aggregates. Anionic micelles strongly speed the complexation reaction, Which occurs in the micellar phase with the same rate and the same mechanism as in water. The extent of binding of PADA to anionic micelles is similar to that found for the cationic micellar aggregates.     

Regulatory role of surfactants in the kinetics of glucose oxidase-catalyzed oxidation ofd-glucose by ferrocenium andn-butylferrocenium ions

The effect of micelles of different surfactants (cationic, anionic, and neutral) on the kinetics of the glucose oxidase-catalyzed reduction of ferrocenium cations RFc⁺ (R=H, Buⁿ) byd-glucose was studied by spectrophotometry. In micellar media of Triton X-100 and sodium dodecyl sulfate (SDS), the Michaelis dependence of the reaction rate on the HFc⁺ concentration is observed, while this dependence has an extreme character in cationic micelles of cetyltrimethylammonium bromide (CTAB). The nature and concentration of surfactants of all types have a slight effect on the rate of reduction of HFc⁺. The level of enzymatic activity is approximately equal in the case of Triton X-100 and CTAB and is considerably lower in the SDS micelles. On going from HFc⁺ to BuⁿFc⁺, the reaction rate is maximum in the cationic CTAB micelles, the anionic SDS micelles exhibit almost no activity, and the activity has an intermediate value in neutral micelles of Triton X-100. The conditions are presented under which the micellar medium controls the catalytic activity of glucose oxidase with respect to ferrocenium cations. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1795–1801, October, 1997.     

Selective complexation of alkali metal ions and nanotubular cyclopeptides: a DFT study

A density functional theory based on interaction of alkali metal cations (Li⁺, Na⁺, K⁺, Rb⁺ and Cs⁺) with cyclic peptides constructed from 3 or 4 alanine molecule (CyAla3 and CyAla4), has been investigated using mixed basis set (C, H, O, Li⁺, Na⁺ and K⁺ using 6-31+G(d), and the heavier cations: Rb⁺ and Cs⁺ using LANL2DZ). The minimum energy structures, binding energies, and various thermodynamic parameters of free ligands and their metal cations complexes have been determined with B3LYP and CAM-B3LYP functionals. The order of interaction energies were found to be Li⁺ > K⁺ > Na⁺ > Rb⁺ > Cs⁺ and Li⁺ > Na⁺ > K⁺ ? Rb⁺ > Cs⁺, calculated at CAM-B3LYP level for the M/CyAla3 and M/CyAla4 complexes, respectively. Their selectivity trend shows that the highest cation selectivity for Li⁺ over other alkali metal ions has been achieved on the basis of thermodynamic analysis. The main types of driving force host–guest interactions are investigated, the electron-donating O offers lone pair electrons to the contacting LP* of alkali metal cations.     

Fluorimetric Determination of Thiamine with Cobalt(II)

Abstract

A rapid fluorimetric method is reported for the determination of thiamine based upon its interaction with Co(II) ion in the presence of base and a nonionic Triton X-100 micellar medium. The effect of different experimental variables upon the fluorescence intensity were assessed. The detection limit for thiamine is 5.0 × 10^?8M (λ_ex =375nm, λ_em =433nm). The method was successfully applied for determination of thiamine in variety of samples with good accuracy being achieved.     

Solvent/substrate effects on the micelle-catalyzed aquation reactions of some iron(II) phenanthroline complexes, I. Influence of water and acid on the aquation of Fe(Ph2Phen)32+ in acetone

The effects of a substrate additive, H⁺ and solvents (water and acetone), on the micelle-catalyzed aquation of tris-(4,7-diphenyl-1, 10-phenanthroline)iron(II), Fe(Ph₂Phen)₃ ²⁺, have been investigated using^#Triton X-100 micelles. The k₀ vs. [TX-100] profiles at fixed [H₂O] are structured, exhibiting maxima. Catalytic factors of 46.6–171.7 are observed for 5.56×10⁻²≤[H₂O] 55.60×10⁻² mol dm⁻³. On the other hand, at fixed [H⁺], the k₀ vs. [TX-100] exhibit broad maxima. The aquation reaction is inhibited by H⁺ and catalytic factors decrease rapidly and exponentially from 422.5 to 20.9 for 0.20×10⁻³≤[H⁺]≤2.00×10⁻³ mol dm⁻³. The aquation is found to be faster (ca. 160–1200 fold) in acetone than in the aqueous medium depending on the added [H₂O]. These observations are rationalized on the basis of a proposed modified lamellar structure for the Triton X-100 (TX-100) micelles in which direct substitution of water molecules into the coordination sphere of the complex occurs.     

Photoinduced membrane potential changes. Bi-ionic potential across poly(vinyl chloride) membranes entrapping a photoresponsive bis(15-crown-5) derivative and the effects of photoirradiation

Bi-ionic potential (BIP) across poly(vinyl chloride) membranes containing azobenzene-modified bis(15-crown-5) was measured in the presence of alkali-metal chlorides. The BIP measurements revealed the cation selectivity sequence of the membranes (K⁺ > Rb⁺ > Cs⁺ ? Na⁺ > Li⁺), which agreed well with the potentiometric selectivity order of 15-crown-5–based ion-selective electrodes developed so far. UV-light irradiation induced the positive or negative shift of BIP. The magnitude and sign of the photoinduced potential shift depended considerably upon the kind and concentration of electrolytes and, as well, the direction from which the membrane was irradiated. The results were explained in terms of the surface-potential changes induced by light irradiation.     

Modification of human erythrocyte membrane potentials by the action of the polyoxyethylene detergent Triton X-100

Triton X-100 in sublytic concentrations causes a marked increase in human erythrocyte membrane permeability to cations with small selectivity to K⁺ ions. This membrane permeabilization induces modification of membrane potential: hyperpolarization in low K⁺ media and depolarization in high K⁺ media. Since the specificity of the K⁺-ionophorous action of Triton X-100 is very low in comparison with valinomycin, the membrane potential changes are only in the range of −9 to +5 mV. It is suggested that they are determined by the generation of a diffusion potential across the membrane, although the influence of Triton X-100 on the potentials at cell surfaces cannot be neglected.     

Thermal instability of organic esters and ethers with deposited lithium in lithium-ion battery

The thermal instabilities of deposited lithium with electrolytes in lithium-ion batteries are simulated by the reactions between metallic lithium with organic esters and ethers. Exothermic onset temperatures and enthalpy changes are measured and analyzed by differential scanning calorimetry. In this study, heat of reactions in lithium with eight different formations of esters and ethers are determined which are consistent to the data of lithiated graphite (LiC₆) reacted with electrolytes in literature. Furthermore, violently exothermic reactions with enthalpy larger than 1,000 J g^?1 and onset temperature lower than 120 °C are further conducted by the confinement test to verify the worst scenarios and consequences of lithium-ion batteries encountered any kind of abuses. Thermal instability of metallic lithium with organic esters in descending order determined to be Li + EB (70 °C)>Li + MB (73.1 °C)>Li + EA (90.8 °C). Finally, thermal hazard data such as onset temperature, maximum self-heat rate, maximum temperature, and maximum pressure of lithium reacted with esters and ethers are compared, evaluated, and some conclusion and suggestions are made.     

Simultaneous Determination of Gallium(III) and Indium(III) in Urine and Water Samples with Cloud Point Extraction and by Inductively Coupled Plasma Optical Emission Spectrometry

A simple, sensitive, and selective method for the determination of gallium and indium in different samples at trace levels is presented. This method was based on complexation of analyzes with 2-(5-bromo-2- pyridylazo)-5-diethylaminophenol (5-Br-PADAP) in the presence of t-octylphenoxy-polyethoxyethanol (Triton X-100). After phase separation, the analyzed concentrations were determined by inductively coupled plasma optical emission spectrometry. Quantitative extraction of gallium and indium was performed at pH 7.0, 1.7 mmol L^?1, 5-Br-PADAP, 1.3% (w/v) Triton X-100 and at 75°C. The relative standard deviations (RSD) of this method were between 0.3% and 1.6% (C = 20 ng mL^?1, n = 9). The calibration curve is linear over the concentration range 6–200 ng mL^?1 for gallium and 2–200 ng mL^?1 for indium, respectively. The limits of detection (LOD) for gallium and indium were 0.72 and 0.28 ng mL^?1, respectively. The results showed the developed method was not susceptible to matrix effects, providing recoveries between 98% and 102%. The accuracy of the developed method was evaluated by the analysis of spiked certified reference materials. The developed method was successfully applied to gallium and indium determination in urine and lake water with satisfactory results.     

Extraction of lanthanide ions from acidic and strongly acidic media by phosphine oxide derivatives using temperature-induced phase separation

A composite for the extraction of lanthanide ions from strongly acidic media by temperature-induced phase separation was designed based on the nonionic surfactant Triton X-100 and new phosphine oxide derivatives. The dependence of the efficiency and selectivity of micellar extraction on the length of the hydrophobic substituent at the P=O group is determined by both the influence of hydrophobic substituents on the electron-donor capacity of the P=O group and the solubility of phosphine oxides in aqueous and micellar phases. The nitric acid concentration was found to influence the efficiency of extraction of lanthanide ions by phosphine oxides with different structures. An increase in the concentration of nitric acid in an aqueous medium from 0.1 to 1 mol L⁻¹ leads to a decrease in the degree of extraction by water-soluble derivatives and a substantial increase in the degree of extraction by phosphine oxides, which are soluble only in the micellar phase of Triton X-100.     

Colorimetric determination of arylamines and sulphonamides by diazotization and coupling in a micellar solution

The use of a micellar solution as a means for improving the colorimetric determination of arylamines by diazotization and coupling is studied. Sodium dodecylsulphate (SDS), Triton X-100 (TX-100) and N-cetylpyridinium chloride (NCPC), together with the diazotizable substances aniline and sulphanilic acid and the coupling agents 1-naphthylamine and N-(1-naphthyl)ethylenediamine are used as model compounds. The protonation constants of the dyes follow the order SDS>H₂O>TX-100>NCPC. In an SDS micellar solution the coupling rate increases greatly, allowing the rapid formation of the protonated dyes in an acetate buffer. Other advantages are the possibility of analysing very non-polar samples and of using a wider range of diazotizable substances and substrates. A procedure for the determination of 10–100 μg of aniline in an SDS micellar solution is proposed. The procedure is applied to the determination of sulphonamides in pharmaceutical preparations.     

TIME-RESOLVED SPECTROSCOPIC STUDIES ON PHOTOPHYSICAL PROPERTIES OF BENOXAPROFEN IN MICELLAR SOLUTIONS: AN INTRAMICELLAR FLUORESCENCE QUENCHING

The micellar dependencies of the photophysical properties of benoxaprofen (BXP), a 2-phenyl benzoxazole derivative, have been investigated using fluorescence spectroscopy and laser flash photolysis techniques. The fluorescence of BXP in aqueous solution has been observed to be remarkably quenched upon addition of a surfactant, cetyltrimethyl ammonium bromide (CTAB) or Triton X-100, in contrast to its enhancement in sodium dodecyl sulfate (SDS) micellar solution. Time-resolved fluorescence measurements show that the fluorescence decays biexponentially in the micellar solution, indicating the relaxation of micellar environments surrounding the excited BXP. The major component of fluorescence lifetimes in CTAB or Triton X-100 micellar phase is even shorter (330–427ps) than in SDS micellar phase (731 ps). The nonradiative decay constants are significantly larger (ca 3.0 times 10⁹ s^?1) in the CTAB or Triton X-100 micellar phase than in SDS micelles by a factor of ca 10. The major nonradiative decay is interpreted to be the internal conversion due to nuclear geometric change of BXP in the first excited singlet state. This is consistent with the observation that the quantum yields of intersystem crossing are very low (less than 0.01) in the micellar solutions as determined by the laser flash photolysis technique. The laser-induced transient absorption spectrum of BXP in CTAB or Triton X-100 micellar solution shows that the decay kinetics of the transients in CTAB or Triton X-100 are significantly different from first order kinetics in SDS.     

Determination of trace uranyl ions in aquatic medium by a useful and simple method

Determination of trace uranyl ions was performed by using mixed micellar system and spectrophotometric determination. The method is based on cloud point extraction of uranyl ions after formation of an ion-association complex in the presence of Celestine Blue and sodium dodecyl sulfate. Then, the formed complex was extracted to non-ionic surfactant phase of Triton X-114 at pH 8.0. The optimal extraction and reaction conditions (e.g. concentrations and types of surfactants, concentration of complex forming agent, incubation conditions) were studied and analytical characteristics of the method (e.g. limit of detection, linear range, pre-concentration factor) were obtained by experimental studies. Linearity was obeyed in the range of 50–1,500 ng mL^?1 for uranium(VI) ion and the detection limit of is 14.20 ng mL^?1. The interference effects of common ions were also tested and validation studies were performed by using recovery test. The method was applied to the determination of uranium(VI) in several real samples.