Aqueous Sodium Dodecyl Sulfate Research Articles

Estimation of micellization parameters of aqueous sodium dodecyl sulfate from conductivity data

The cmc (critical micelle concentration), counterion binding parameter (β), and aggregation number (n) of aqueous sodium dodecyl sulfate (SDS) are estimated from conductivity data at various temperatures and salinities. The conductivity models used are based on mass action micellization thermodynamics and the Debye-Huckel-Onsager conductivity theory. With rigorous parameter estimation methods, the models are optimally fit to previous literature data. Moreover, new data were taken with an experimental design which is based on the precise solution of the inverse problem

Micelles of SDS Surfactants in Concentrated NaCl Solutions

AbstractWe investigated the aggregation behavior of rod‐like micelles of sodium dodecyl sulfate (SDS) in concentrated NaCl solution by quasi‐elastic light scattering (QLS) and viscosity measurement over a range of temperature (25 °C to 50 °C) and NaCl concentration. The reduced viscosity of aqueous SDS in the presence of NaCl has been measured by an Ubbelohde‐type capillary viscometer. We show mean hydrodynamic radius of micelles can be determined from viscosity data. We also determined mean hydrodynamic radius using quasi‐elastic light scattering. Micellar size decreases with increasing temperature, whereas it increases with increasing ionic strength. The results of viscosity and dynamic light‐scattering measurements are interpreted as the extension of length of rod‐like micelles. We compare viscosity and light scattering experimental results.

The Affinity Purification of Serum Carboxylesterase from Pigeons Columba livia

AbstractPreliminary studies indicate that 3‐butylthio‐1,1,1‐trifluoropropan‐2‐one (BTFP) is a potent, competitive inhibitor of pigeon serum α‐naphthyl acetate esterase (α‐NAE); I50, 9·5 nM.The synthesis of an affinity resin with 3‐(4‐mercaptobutylthio)‐1,1,1‐trifluoropropan‐2‐one (MBTFP) as the ligand is reported; α‐NAE from serum bound strongly to this. To remove protein from the resin, washing with 3‐octylthio‐1,1,1‐trifluoropropan‐2‐one (OTFP) and subsequent boiling in aqueous sodium dodecylsulfate (SDS) were employed. Recovered protein run on SDS‐PAGE showed a single major protein band at 58–60 kDa which agrees well with previous determinations of the molecular weights of carboxylesterases.

Solute partition study in aqueous sodium dodecyl sulfate micellar solutions for some organic reagents and metal chelates

The partition constants (Kd) have been estimated for nitrophenols, thiazolylazo dyestuffs and metal chelate compounds into the sodium dodecyl sulfate (SDS) micellar phase at an ionic strength of 0.10M [(H+, Na+)Cl−] and at 20 °C. The equilibrium partition data obtained by batch-wise solution spectrophotometry (equilibrium shift method) agree well with those by the micellar electrokinetic capillary chromatography (MECC) with the SDS micellar pseudo-stationary phase. The MECC clearly discriminates a very small difference (0.03) in the logKd values of some metal chelates. The plot of theKd values with the van der Waals volume of the solute molecules obviously shows the leveling-off of theKd values over solute size near 110 ml/mol, which seems to be consistent with the results obtained in the Triton X-100 micellar system. This phenomenon arises most probably from the rigidity of the micellar pseudo-phase (a micellar volume-constraint effect) in sharp contrast with true two-phase partitioning such as solvent extraction systems.

The effect of area of application on the intensity of response to a cutaneous irritant

The intensity of the cutaneous response was assessed after application of a standard irritant to increasing areas of normal forearm skin. Twenty subjects were tested to determine the minimal irritant dose (MID) to dilutions of aqueous sodium dodecyl sulphate. Each subject was then treated under occlusion for a period of 24 h with different areas of filter paper (9, 25, 100, 225 and 400 mm2) soaked with the concentration required to give the individual's MID. At 25 and 48 h the degree of erythema was assessed using a 0-4 arbitrary scale, a 10-cm visual analogue scale (VAS) and an erythema meter. Cutaneous blood flow was measured with a laser-Doppler device and cutaneous oedema measured by pulsed A-scan ultrasound. The results at 25 and 48 h were almost identical. Both forms of visual assessment (arbitrary scale and VAS) showed an increase in perceived erythema with increasing area and this was confirmed by the erythema meter. Further area-related changes were noted with both cutaneous blood flow and ultrasound measurements.

ζ potential measurement by means of the plane interface technique

The ζ potential of quartz and sapphire plates in contact with aqueous solutions was measured by means of the plane interface technique, which involves establishing the liquid flow velocity—depth profile using reference (polystyrene latex) particles. The electroosmotic velocity obtained by extrapolation of the velocity profile to the cell wall permits calculation of the ζ potential of the cell wall—solution interface. The plane interface technique was also used to obtain the ζ potential at aqueous sodium dodecyl sulfate (SDS) solution surfaces with an open cell in which the upper boundary consists of an air—solution interface and the lower boundary, a quartz—solution interface. It was essential to eliminate the meniscus in the open cell to obtain normal velocity profiles. The ζ potential of the aqueous SDS solution surface paralleled the Stern potential, calculated from the surface tension—SDS concentration data by use of Gibbs adsorption equation and Gouy-Chapman theory, though the former was larger in magnitude than the latter.

Photophysical and photochemical properties of rhodamine 6G in alcoholic and aqueous sodium dodecylsulphate micellar solutions

The photodecomposition of the rhodamine 6G (R6G) dye dissolved in n-alcohols and aqueous sodium dodecylsulphate (SDS) micellar solution was investigated under continuous UV-visible illumination. The results indicate that in alcohol solution the photodecomposition efficiency increases with the dye concentration. It also depends on the nature of the alcohol the lowest efficiency being observed in ethyleneglycol. The mechanism involves the electron transfer reaction of the triplet excited state with a ground state dye molecule (T + S 0 → R + + R − . In aqueous SDS micellar solution, the R6G cation is embedded in the hydrophobic interior of the micelle close to the negatively charged sulphate end groups. We show that a rather high concentration (3 × 10 −3 M) of R6G can be dissolved in 10 −1 M SDS aqueous solution, protecting R6G from the electron transfer reaction and secondary decomposition reactions.

A comparison of the polysaccharides extracted from dried and non-dried walls of suspension-cultured sycamore cells

Suspension-cultured sycamore cells ( Acer pseudoplatanus) were disrupted in aqueous K-Pi buffer and the insoluble residue (the cell wall) purified by extraction with organic solvents and air-dried (dry cell walls) or by washing with aqueous sodium dodecyl sulphate and stored frozen (wet cell walls). Polysaccharides solubilized from the purified wet and dry cell walls by enzymatic digestion and chemical extraction were isolated and their glycosyl-residue compositions compared. No significant differences were found in the types or yields of the polysaccharides solubilized by enzymatic digestion and chemical extraction of the wet and dry cell wall preparations. Moreover, the glycosyl-residue compositions of the so-called ‘α-cellulose’ fraction that remains after extraction of the wet and dry cell wall preparations with alkali was indistinguishable from the glycosyl-residue compositions of the walls prior to extraction.

The pH dependence of dispersion of TiO2 particles in aqueous surfactant solutions

The pH dependence of dispersion of titanium dioxide (TiO2) particles has been examined in the presence of surfactant molecules in water. Whereas particles were dispersed in water at acid and alkaline regions rather than at neutral region, the dispersion was enhanced at neutral region in an aqueous sodium dodecyl sulfate (SDS) solution and at acid and alkaline regions in an aqueous dodecyldimethylamine oxide (C12DAO) solution. Considering the pH dependence of zeta potential, the adsorption models of surfactant molecules on a particle were estimated on the basis of the modes of hemimicelle and double-layer compression. While the particles that adsorbed Al3+ were remarkably dispersed around pH 6, their dispersion does not largely depend on pH in the addition of SDS, indicating the adsorption of SDS molecules to form double-layer compression in the whole pH region. Dynamic light-scattering measurement and electron microscopic observation suggested that the particles were dispersed in water as small flocs.

Octaethylporphyrinate haem complexes encapsulated inside aqueous detergent micelles: a spectroscopic study

NMR and optical spectral studies have been made for monomeric aqua and hydroxo complexes of iron(III) 2,3,7,8,12,13,17,18-octaethylporphyrin in aqueous sodium dodecyl sulphate (sds) detergent micellar solutions. Both the aqua and hydroxo complexes are found to be high spin (S= 5/2). The pKa for the aqua ⇌ hydroxo equilibrium was found to be 4.8. Iron(II) complexes of octaethylporphyrin in different spin states and co-ordination geometries have also been stabilized in aqueous micellar solution. The detailed structural disposition of the porphyrin complex and the conformation of the surfactant molecules inside the micellar cavity have also been investigated using 13C NMR spectra of aqueous sds detergent micelles containing the complex. The average values of the distances of the different carbon centres in a surfactant molecule from the iron obtained from spin-lattice relaxation enhancement measurements were fitted to a spherical model of micellar structure to obtain the average configuration of the detergent molecules and the position of the complex inside the micelles.

Effect of sodium dodecyl sulfate concentration on the attachment between mercury and argon bubbles in aqueous solutions

The attachment between mercury and argon gas bubbles was investigated at various polarization potentials E (volt vs SCE) of a mercury electrode in aqueous sodium dodecyl sulfate (SDS) solutions in the presence of 0.01 M NaClO 4. It was found that the range of E for sponteneous attachment was about −0.3 ∼ −0.6 V when SDS concentration was less than 5 × 10 −6 M, while no sponteneous attachment was observed at SDS concentrations higher than 5 × 10 −6 M. Under the conditions of spontaneous attachment, the Stern potentials of both mercury and bubbles were negative and the surface coverages of DS − ions on the two surfaces were less than 10% and 2%, respectively, assuming a cross-sectional area of the alkyl chain of 18.5 Å 2. Experimental results are discussed in terms of the heterocoagulation theory. The existence of an additional attractive hydrophobic force is suggested and an attempt is made to reveal the dependence of the hydrophobic force on the surface coverage of the surfactant.

Conformational requirement of signal sequences functioning in yeast: circular dichroism and proton nuclear magnetic resonance studies of synthetic peptides

Recently, we have designed a series of simplified artificial signal sequences and have shown that a proline residue in the signal sequence plays an important role in the secretion of human lysozyme in yeast, presumably by altering the conformation of the signal sequence [Yamamoto, Y., Taniyama, Y., & Kikuchi, M. (1989) Biochemistry 28, 2728-2732]. To elucidate the conformational requirement of the signal sequence in more detail, functional and nonfunctional signal sequences connected to the N-terminal five residues of mature human lysozyme were chemically synthesized and their conformations in a lipophilic environment [aqueous trifluoroethanol (TFE) or sodium dodecyl sulfate micelles] analyzed by circular dichroism (CD) and 1H nuclear magnetic resonance (NMR) spectroscopy. The helix content of the peptides, including functional (L8, CL10) and nonfunctional (L8PL, L8PG, L8PL2) signal sequences, was estimated from CD spectra to be 40-50% and 60-70%, respectively, indicating that the helical structure is more abundant in the nonfunctional signal sequences. Two-dimensional NMR analyses in 50% TFE/H2O revealed that each peptide adopted a helical conformation throughout the sequence except for a few residues at the N- and C-termini. Furthermore, H-D exchange experiments indicated that the helical structure of the C-terminal region of the functional signal sequences (L8 and CL10) was less stable than that of the nonfunctional signal sequences (L8PL and L8PL2). On the basis of these results, a model was developed in which the functional signal sequence is inserted in the membrane with a helical conformation and the C-terminal helix unraveled in an extended conformational form through an interaction with the signal peptidase.

New electroactive 2-n-octyloxy-5,6,11,12- tetrathiotetracene dodecylsulfate cation radical salt: Formation at the air-water interface and characteristic properties of Langmuir-Blodgett films

The formation and characteristic properties of the new electroactive 2- n-octyloxy-5,6,11,12-tetrathiotetracene dodecylsulfate cation radical salt 1 are described. The salt is prepared in monomolecular layers at the air-water interface according to the following steps: (a) neutral donor molecules of 2- n-octyloxy-5,6,11,12-tetrathiotetracene 2 are spread on an aqueous sodium dodecylsulfate solution, (b) the monolayer of 2 thus prepared is gradually oxidized by air under formation of cation radicals, while (c) the dodecylsulfate ions 3 present in the subphase are inserted in the monolayer as counterions of the cation radicals. This insertion is accompanied by an expansion of the monolayer by about 70% of the original area. The oxidized monolayers can be easily deposited on different substrates by the Langmuir-Blodgett (LB) technique. Characterization of the LB films by various spectroscopic methods such as UV-visible, IR and ESR spectroscopies indicates that the films consist exclusively of the cation radical salt 1. Electron spin resonance spectroscopy studies suggest that the tetrathiotetracene molecular plane is oriented perpendicular to the substrate plane. It is demonstrated by conductivity measurements and cyclic voltammetry that the LB films are poorly conducting but can be reversibly oxidized and reduced electrochemically.

Proton and carbon-13 NMR studies on the structure of micelles encapsulating hemes in aqueous sodium dodecyl sulfate solutions

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTProton and carbon-13 NMR studies on the structure of micelles encapsulating hemes in aqueous sodium dodecyl sulfate solutionsShyamalava. MazumdarCite this: J. Phys. Chem. 1990, 94, 15, 5947–5953Publication Date (Print):July 1, 1990Publication History Published online1 May 2002Published inissue 1 July 1990https://doi.org/10.1021/j100378a062RIGHTS & PERMISSIONSArticle Views138Altmetric-Citations23LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (870 KB) Get e-Alerts

Voltammetric detection of micelle formation

Voltammetry at the rotating disk electrode of a water-and-oil-soluble electroactive probe ( N,N-diethyl-3-methyl- p-phenylene diamine, PPD) was used to detect the onset of micellization in aqueous sodium dodecyl sulfate (SDS), di-/triisopropyl naphthalene sulfonate (DTINS), and cetyltrimethylammonium bromide (CTAB) systems in 0.1 M NaCl at 25°C and pH 10. Critical micelle concentrations in agreement with values determined by other methods were obtained. Micellar/aqueous phase distribution coefficients were estimated by modeling the variation of limiting current with amphiphile concentration. Distribution coefficients of 324 and 73 were obtained for the SDS and DTINS systems, respectively. In the CTAB system, sequential distribution coefficients of 272 and 88, respectively, were obtained below and above a “second CMC” (0.001 M), which corresponds to the onset of a transition in micellar morphology.

Surfactant and cyclodextrin fluorescence enhancement of dansylamino acids and of thiol-ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulphonate derivatives

The effects of aqueous cyclodextrin and sodium dodecyl sulphate and of non-ionogenic Triton solutions on the fluorescence emission of ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulphonate-labelled glutathione, acetylcysteine and cysteine and of some dansylated amino acids were investigated. Depending on the type and concentration of enhancer used, fluorescence enhancements up to 8-fold were found in comparison with the values in pure solvent. These organised systems show promise for general luminescence-based analytical work.

Composition of a liquid crystalline phase formed between aqueous surfactant solutions and oily substances

AbstractDifferential scanning calorimetry (DSC) was applied to determine the composition of a liquid crystalline (LC) phase formed between an aqueous solution of sodium dodecyl sulfate (SDS) and octanol under various conditions. The concentrations of three components, SDS, water, and octanol, contained in the LC phase were determined approximately from the DSC melting peak areas.The composition of the LC phase varied with time within the LC region in the phase diagram reported in the literature. The change of the octanol concentration in the LC phase was correlated to the process in which octanol is gradually incorporated into the LC phase and then released into the exterior aqueous SDS solution. Increasing temperature facilitated such a process.

Counterion association to aqueous sodium dodecyl sulfate micelles in the presence of organic additives

The effect of polar, nonpolar, and mixed polar-nonpolar additives on the counterion association, the structure, and the size of aqueous sodium dodecyl sulfate micelles has been examined by measuring the conductivity, the viscosity, and the electromotive force at 298.15 K. Octane does not affect the degree of counterion association, but the mobility of the micelles decreases. This is mainly due to an increased micellar volume. Small quantities of 1-butanol and 1-hexanol decrease the degree of counterion association. At higher hexanol molalities larger micellar aggregates, rod- or disk-like micelles are formed. Long-chained α,ω-alkanediols, 1,9-nonanediol and 1,10-decanediol, also reduce the degree of counterion association. The shorter diols apparently affect the micellar system mainly through their effect on the solvent. The effect of the mixed additives is intermediate to that of pure components. Changes in the aggregation number, the micellar radius, and the number of associated counterions have been estimated from the conductivity and electromotive force measurements. Addition of octane does not affect the degree of associated counterions, but the micellar aggregation number increases. Addition of hexanol lowers both the micellar aggregation number and the fraction of associated counterions.

Acid–base equilibria in aqueous micellar solutions. Part 3.—Azine derivatives

The acid–base behaviour of two azine derivatives, viz. neutral red and acridine, in aqueous non-ionic Brij-35 and n-octyl β-D-glucoside micellar solutions, in aqueous anionic sodium dodecyl sulphate micellar solutions and in 1,4-dioxane–water mixtures have been investigated. The factors primarily responsible for the difference between the pKavalue of an azine derivative in pure water and its apparent pKa value when it is located quantitatively within the micelle–aqueous solution interface have been determined. For the non-ionic micellar systems, the difference can be explained solely in terms of the different intrinsic solvent properties of the two solvating media. For the anionic micellar systems three major factors are considered to be responsible for the difference. These factors are the electrostatic micellar surface potential, the interfacial solvent characteristics, and specific molecular interaction between the cationic protonated moieties of the azine derivatives and the anionic surfactant headgroups.

Tracer Diffusion of Tris(1,10-phenanthroline)iron(II) Cation in Aqueous Sodium Dodecyl Sulfate Solutions. Strong Premicellar Interactions

Abstract Tracer diffusion coefficient of Fe(phen)32+ (phen = 1,10-phenanthroline) has been determined in aqueous sodium dodecyl sulfate (NaDS) solutions at 298.2 K using Taylor dispersion technique. Below the critical micelle concentration (cmc) of NaDS (3–8 mM++), the diffusion coefficient is remarkably low, and increases with increasing concentration of NaDS.