Sodium Dodecyl Phosphate Research Articles

Increased effectiveness of the flotation separation of hornblende and magnesite by adding citric acid as depressant

Abstract The microflotation experiments were systematically carried out to investigate the inhibitory effect of citric acid (CA) on the flotation behavior of hornblende and magnesite. When the mixture consisted of sodium oleate and dodecyl phosphate was utilized as a mixed trapping reagent, CA could obviously inhibit the hornblende flotation but had little inhibitory effect on magnesite flotation. The desilication of magnesite flotation was accomplished when CA was employed as the hornblende inhibitor. Moreover, to reveal the adsorption mechanism of CA on the surfaces of hornblende and magnesite, a series of surface analysis techniques, such as X-ray photoelectron spectroscopy (XPS), zeta potential and Fourier transform infrared spectroscopy (FTIR), were conducted. Based on the zeta-potential and FTIR analyses, it is revealed that CA or CA together with collector (sodium oleate and dodecyl phosphate mixture) was applicable for the magnesite flotation tests. In the meanwhile, the introduced CA had obviously hindered the adsorption of sodium oleate and dodecyl phosphate mixtures on the hornblende surface, resulting in a significant difference in the flotation performance of hornblende and magnesite minerals. Moreover, XPS measurements revealed that the strong adsorption of CA on the hornblende surface can be ascribed to its affinity for the negative electron groups of CA and Ca ions.

Cytotoxic Effect of Red Sandal Mediated Silver Nanoparticles Mouthwash Using Brine Shrimp Lethality Assay: An In-vitro Study

Background: Silver Nanoparticles (AgNP) plays a crucial role in nanoscience, nanotechnology and nanomedicine. AgNP has antibacterial, antifungal, antiviral, anti-inflammatory, anti-antigenic, anticancer and cytotoxic properties. Cytotoxic effects of mouthwashes on the gingival tissue have always been a priority. Pterocarpus santalinus, with the common name of red sandalwood. The aim of the study is to evaluate the cytotoxic effect of red sandal mediated silver nanoparticles mouthwash using brine shrimp lethality assay.
 Materials and Methods: The mouthwash was prepared using red sandal mediated silver nanoparticles, ethanol, distilled water, sucrose, sodium benzoate, clove oil, sodium dodecyl phosphate with 0.1% in concentration. The methodology includes green synthesis of Red sanders mediated Silver Nanoparticles synthesis followed by tests for Cytotoxic effect using mouthwash.
 Results: Red sanders mediated silver nanoparticles have high potent cytotoxic potential, it has been proved with the help of brine shrimps. LD50 concentration was obtained to be 80µL, with half the population of nauplii in the respective well surviving post incubation. 
 Conclusion: From the observed result, it has been concluded that Pterocarpus santalinus/red sandal mediated silver nanoparticles mouthwash has a considerably moderate cytotoxic effect. It is a rich source of various potential phytochemicals and is a simple, rapid, stable and cost effective method for nano based medical applications.

Template effect of phosphate surfactant on formation of hydroxyapatite nanostructures with various shapes

Hydroxyapatite nanostructures with various shapes have been prepared by phosphate surfactant self-assembly in aqueous solution. The hydroxyapatite structure is greatly influenced by the sodium dodecyl phosphate (SDP) concentration. X-ray diffraction, transmission electron microscopy measurements, thermogravimetric analysis, and Fourier transform infrared spectra were performed to investigate the nanostructures. Spindle-type nanoparticles formed by oriented attachment of hydroxyapatite nanocrystals were obtained with low SDP concentration, whereas rod-shaped and sheet-like nanostructures formed in the two-dimensional water phase of the lamellar structure with high SDP concentration. These results indicate that SDP molecules play a critical role in formation of hydroxyapatite nanostructures.

In vitro test systems supporting the development of improved pest control methods: a case study with chemical mixtures and bivalve biofoulers

Using the bivalve macrofouler Corbicula fluminea, the suitability of in vitro testing as a stepping stone towards the improvement of control methods based on chemical mixtures was addressed in this study. In vitro cholinesterase (ChE) activity inhibition following single exposure of C. fluminea tissue to four model chemicals (the organophosphates dimethoate and dichlorvos, copper and sodium dodecyl phosphate [SDS]) was first assessed. Consequently, mixtures of dimethoate with copper and dichlorvos with SDS were tested and modelled; mixtures with ChE revealed synergistic interactions for both chemical pairs. These synergic combinations were subsequently validated in vivo and the increased control potential of these selected combinations was verified, with gains of up to 50% in C. fluminea mortality relative to corresponding single chemical treatments. Such consistency supports the suitability of using time- and cost-effective surrogate testing platforms to assist the development of biofouling control strategies incorporating mixtures.

Evaluation of hydroxyapatite nanoparticles synthesized with phosphate surfactant by means of G‐SIMS and g‐ogram

Inorganic and organic composite materials have been utilized as high‐functional materials over a wide variety of industrial fields. Understanding interactions between inorganic and organic components is important for their further improvements. In this study, hydroxyapatite (HAp) nanoparticles synthesized with sodium dodecylphosphate (SDP) were evaluated using gentle‐SIMS (G‐SIMS) and g‐ogram, which are spectrum analysis methods for time‐of‐flight SIMS. As a result, G‐SIMS and g‐ogram indicates that SDP molecules are adsorbed onto the surface of HAp nanoparticles and partly used to form HAp nanostructures. The more intact fragment ions indicated by G‐SIMS and g‐ogram imply that lamellar structures are formed in HAp sample synthesized with the high SDP concentration. Therefore, it is suggested that G‐SIMS and g‐ogram provide useful information for understanding chemistry of fine structures within inorganic and organic composite materials. Copyright © 2014 John Wiley & Sons, Ltd.

Structure Formation in Metal Complex/Polymer Hybrid Nanomaterials Prepared by Miniemulsion

Polymer/complex hybrid nanostructures were prepared using a variety of hydrophobic metal β-diketonato complexes. The mechanism of structure formation was investigated by electron paramagnetic resonance (EPR) spectroscopy and small-angle X-ray scattering (SAXS) in the liquid phase. Structure formation is attributed to an interaction between free coordination sites of metal β-diketonato complexes and coordinating anionic surfactants. Lamellar structures are already present in the miniemulsion. By subsequent polymerization the lamellae can be embedded in a great variety of different polymeric matrices. The morphology of the lamellar structures, as elucidated by transmission electron microscopy (TEM), can be controlled by the choice of anionic surfactant. Using sodium alkylsulfates and sodium dodecylphosphate, "nano-onions" are formed, while sodium carboxylates lead to "kebab-like" structures. The composition of the hybrid nanostructures can be described as bilayer lamellae, embedded in a polymeric matrix. The metal complexes are separated by surfactant molecules which are arranged tail-to-tail; by increasing the carbon chain length of the surfactant the layer distance of the structured nanomaterial can be adjusted between 2 and 5 nm.

Effect of anionic-lipid-molecule geometry on the structure and properties of liposome-polycation complexes

The influence of anionic amphiphilic compounds that have different geometric shapes and become incorporated into bilayers on the polycation-mixed liposome interaction and the structure and properties of the resulting complexes is analyzed. Phosphatidylserine, cardiolipin, and sodium dodecyl phosphate are used as anionic lipids, and poly(N-ethyl-4-vinylpyridinium bromide) and polylysine are used as polycations. Polycation adsorption on the surfaces of all examined types of liposomes is accompanied by the neutralization of their charge, an increase in the size of particles of the systems, and quenching of fluorescence labels. Liposomes whose membranes contain incorporated cylindrical phosphatidylserine molecules retain their integrity during contact with polycations. The resulting complexes quantitatively dissociate into initial components during an increase in the salt concentration in the surrounding solution. In the case of liposomes with asymmetric anionic lipids, that is, cardiolipin and sodium dodecyl phosphate, the conditions of retaining the membrane integrity and reversible complexation are fulfilled only at relatively low molar fractions of both lipids. The obtained data witness the decisive effect of the geometry of anionic lipid molecules on the stability of complexes formed from mixed liposomes and polycations.

Improved Adsorption of Basic Protein on Hydroxyapatite Nanoparticles Synthesized Using a Lamellar Template of Sodium Dodecylphosphate

Abstract We synthesized hydroxyapatite (HAp) nanoparticles using a lamellar phase, which was formed using a phosphorous surfactant, sodium dodecylphosphate (SDP). The HAp nanoparticles synthesized using SDP, after calcination, adsorbed more egg white lysozyme compared to that synthesized without SDP.

Significantly enhanced production of recombinant nitrilase by optimization of culture conditions and glycerol feeding

The production of a recombinant nitrilase expressed in Escherichia coli JM109/pNLE was optimized in the present work. Various culture conditions and process parameters, including medium composition, inducer, induction condition, pH and temperature, were systematically examined. The results showed that nitrilase production in E. coli JM109/pNLE was greatly affected by the pH condition and the temperature in batch culture, and the highest nitrilase production was obtained when the fermentation was carried out at 37°C, initial pH 7.0 without control and E. coli was induced with 0.2 mM isopropyl-β-D-thiogalactoside at 4.0 h. Furthermore, enzyme production could be significantly enhanced by adopting the glycerol feeding strategy with lower flow rate. The enzyme expression was also authenticated by sodium dodecyl phosphate polyacrylamide gel electrophoresis analysis. Finally, under the optimized conditions for fed-batch culture, cell growth, specific activity and nitrilase production of the recombinant E. coli were increased by 9.0-, 5.5-, and 50-fold, respectively.

Dissolution and Protection of Aluminium Oxide in Corrosive Aqueous Media—An Ellipsometry and Reflectometry Study

Dissolution of alumina has been studied from wafers in aqueous solution by means of ellipsometry and reflectometry. It was discovered that the dissolution of aluminium oxide is promoted by ethanol amines like N,N-bis(2-hydroxyethyl)glycine and triethanolamine, and that this dissolution is retarded by sodium dodecyl sulphate (SDS) and stopped by sodium dodecyl phosphate (SDP). The protective property of SDP to alumina is in perfect agreement with earlier found results which showed that SDP efficiently hinders the oxidation of aluminium pigment flakes in alkaline aqueous solution. Ethanol amines are used to regulate the pH in waterborne paints and printing ink formulations. However, the aggressive properties of ethanol amines to alumina are a problem for these kinds of formulations. This may be attributed to the formation of water soluble complexes between ethanol amines and Al(III). To increase the shelf life of aluminium pigments in waterborne formulations in the future, the ethanol amines then need to be replaced by other, less aggressive, bases if possible.

Effect of sample pre-treatment on the determination of steroid esters in hair of bovine calves

The effect of three sample pre-treatment steps, washing, cutting and grinding on the determination of steroid esters in hair is studied. The study is performed by using hair samples obtained after pour-on application of steroid esters to bovine calves. After sample pre-treatment the hair is treated with a mild reducing agent [tris(2-carboxyethyl)phosphine hydrochloride] to extract the steroid esters. After a solid-phase extraction clean-up step the extracts are analysed by using liquid chromatography combined with triple–quadrupole mass spectrometric detection. For the washing step the use of non-organic washing solvents like (warm) water and a solution of 0.1% sodium dodecyl phosphate and organic solutions containing different percentages of methanol are tested. By using the non-organic solvents and the organic solvents with a percentage of methanol <20% the recovery results are as good as the results obtained without washing the hair. Cutting the hair samples increases the analyte recoveries of incurred steroid esters by 20% compared to the non-cut hair. The analyte recoveries of cut hair samples are about 60–80% that of ground hair samples. The obtained surface expansion of hair samples by grinding proves to be necessary in order to achieve the highest possible analyte yields. Finally the use of pressurised liquid extraction (PLE) for the extraction of steroid esters from plain (no washing, cutting or grinding) hair is investigated. The first results show lower (up to 40%) extraction recoveries in comparison with the classical solvent extraction procedures. If the limit of detection requirement is met, PLE may be an alternative for extracting large numbers of hair samples due to the short sample treatment procedure involved.

Adsorption of Sodium Dodecyl Sulfate and Sodium Dodecyl Phosphate on Aluminum, Studied by QCM-D, XPS, and AAS

The adsorption of two anionic surfactants, sodium dodecyl sulfate (SDS) and sodium dodecyl phosphate (SDP), at surfaces of aluminum and aluminum oxide has been studied by means of atomic absorption spectrometry (AAS), X-ray photoelectron spectroscopy (XPS), and quartz crystal microbalance with dissipation monitoring (QCM-D). It was shown that more SDP than SDS binds to the surface and that SDP prevents dissolution of aluminum in water whereas SDS does not. This was not obvious, since the adsorption isotherms of the two surfactants to aluminum pigment powder are quite similar, as shown in an earlier work. The decreased aluminum dissolution with SDP compared to SDS was explained by the formation of a more compact protective layer with less permeability on the aluminum surface with SDP than with SDS. This is explained by differences in complexing ability between the surfactants and the aluminum pigment surface. While SDP is expected to form an inner-sphere complex with aluminum, leading to a lower accessibility of aluminum sites to water, SDS is likely to form a weaker outer-sphere complex.

Surfactant inhibition of aluminium pigments for waterborne printing inks

Micrometre-sized aluminium particles are used as pigments in silver inks and for environmental reasons it is desirable to develop water-based formulations of such pigments. In waterborne coatings, however, aluminium is prone to react with water, with subsequent hydrogen gas evolution and loss of the silvery lustre. The protection against water of aluminium pigments by adsorption of either a nonionic or an anionic surfactant has been evaluated. Phosphate esters with different lengths of the hydrocarbon tail have been synthesised and tested, and were found to provide very effective protection of the pigments. Sodium dodecyl sulphate (SDS), on the other hand, was completely ineffective as inhibitor, even though the adsorption isotherm was about the same as for the structurally similar sodium dodecyl phosphate (SDP). This difference may be explained by formation of different types of complexes with the aluminium oxide surface. Outer-sphere complexes are suggested for SDS, whilst SDP can form more stable inner-sphere complexes. Tests with the non-surface active methyl phosphate as inhibiting agent gave insufficient protection, indicating that surface activity is crucial for the inhibition, and that the use of the phosphates as such is not enough to give proper protection. The work shows that amphiphilic compounds having phosphate as anchoring group are efficient in providing water resistance to aluminium pigments.

Study of Solute Partitioning in Biomembrane−Mimetic Pseudophases by Electrokinetic Chromatography: Dihexadecyl Phosphate Small Unilamellar Vesicles

Solute partitioning into vesicles of dihexadecyl hydrogen phosphate (DHP) was investigated by electrokinetic chromatography (EKC). The ionic double-chain surfactant forms bilayer structures that mimic a biological membrane when dispersed in aqueous media. The linear solvation energy relationship (LSER) was used to gain insights about the nature of interactions and parameters that influence the partitioning process into vesicles, micelles, and n-octanol. The Gibbs free energies of transfer of selected functional groups from aqueous to vesicular phases were compared to those in micellar pseudophases of sodium dodecyl sulfate (SDS) and sodium dodecyl phosphate (SDP). Size and hydrogen bond acceptor strength of solutes are the main factors that determine their partitioning behavior, while dipolarity and polarizability play minor, yet significant, roles. It was determined that the cohesiveness of solute microenvironments in DHP vesicles is between those for micells and n-octanol. Vesicles are weaker hydrogen bond donors and less dipolar than micelles; however, they interact more strongly with the n and π electrons of solutes. Interestingly, as the organization of the pseudophase is enhanced from micelles to vesicles, their microenvironments become closer to that of octanol. Consequently, solute partitioning in vesicle−water correlates better with that in octanol−water than with that in micelle−water. The influence of the presence of cholesterol in the bilayer on the interactive nature of the pseudophase was also investigated.

The impact of buffers and surfactants from micellar electrokinetic chromatography on matrix-assisted laser desorption ionization (MALDI) mass spectrometry of peptides: Effect of buffer type and concentration on mass determination by MALDI-time-of-flight mass spectrometry

This paper describes the effect of various buffers, surfactants, and organic additives commonly encountered in capillary zone electrophoresis and micellar electrokinetic chromatography on the molecular weight determination of peptides by matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry. Signal-to-noise ratio generally decreased with increasing buffer concentration without affecting mass accuracy, but the type of buffer was also important. Good spectra were obtained with an ammonium acetate buffer up to a concentration of 500 m M without impacting ionization of either peptides or other mobile phase constituents. Ionization of organic additives, such as anionic surfactants, non-ionic surfactants, and cyclodextrins was buffer dependent and presented a problem when the mass of the additive was in the range of the peptide mass. Brij ®-35, Tween ®-80, and cyclodextrins all produced prominent spectra of their own in the presence of sodium or potassium containing buffers, but not with ammonium acetate. Cationization of these neutral species with sodium or potassium ions allowed them to acquire a positive charge and produce spectra. In contrast, the ammonium ion appears to be a poor cationizating agent. Ionization of neutral surfactants was suppressed in ammonium acetate without impacting the spectra of peptides. Ammonium acetate buffers containing 30 m M sodium dodecyl phosphate also gave spectra with good signal intensity and no interference from the surfactant. Suppression of peptide ionization in MALDI was a problem when methanol, tetrabutyl amine, or poly(vinyl alcohol) were used with either ammonium acetate, sodium phosphate, and N-(2-hydroxyethyl)piperazine- N-(2-ethansulfonic acid).

Analysis of urine samples containing cardiovascular drugs by micellar liquid chromatography with fluorimetric detection.

A simple direct injection chromatographic procedure with fluorimetric detection is successfully applied to the determination of mixtures of 4 diuretics (amiloride, bendroflumethiazide, piretanide, and triamterene) and 6 beta-blockers (acebutolol, atenolol, labetalol, metoprolol, nadolol, and propranolol), which are usually administered in combinations for the treatment of hypertension, in urine samples. The procedure makes use of C18 columns and micellar mobile phases of sodium dodecyl sulphate (SDS), propanol, and phosphate buffer at pH 3. The adequate resolution of most drugs is obtained with a chemometrics approach where the retention is modeled as a first step using the retention factors in only 5 mobile phases. Afterward, an optimization criterion that takes into account the position and shape of the chromatographic peaks is applied. A mobile phase of 0.11M SDS--8% propanol could resolve mixtures of 8 drugs and was adequate for the analysis of the combinations of diuretic and beta-blocker usually prescribed. However, a mobile phase of larger elution strength, such as 0.15M SDS--15% propanol, is preferred for the analysis of mixtures of amiloride-metoprolol, amiloride-labetalol, and triameterene-propranolol. The method is sensitive enough for the routine analysis of diuretics and beta-blockers at therapeutic urine levels with limits of detection in the 0.5-28-ng/mL range. Urinary excretion studies show that the detection of most drugs is possible up to 24-72 h after their ingestion.

Liquid chromatographic determination of some thiazide diuretics in pharmaceuticals with a sodium dodecyl sulfate mobile phase

A rapid and simple liquid chromatographic procedure that uses micellar mobile phases, containing only sodium dodecyl sulfate (SDS) and phosphate buffer, is reported for the determination of some thiazide diuretics (althiazide, bendroflumethiazide, chlorothiazide, cyclothiazide, hydrochlorothiazide, hydroflumethiazide and trichloromethiazide) in pharmaceuticals. An interpretive optimization procedure, based on an equation that relates the capacity factor with the micellar concentration, indicated the SDS concentration at which the diuretics were best resolved. The determination of hydrochlorothiazide and trichloromethiazide in pharmaceuticals could be achieved with a micellar mobile phase of 0.02 mol l–1 SDS in 0.01 mol l–1 phosphate buffer (pH 7), with retention times below 5 min, but the determination of althiazide and bendroflumethiazide required a micellar mobile phase of 0.15 mol l–1 SDS at the same pH, with retention times below 7 min. The recoveries from the pharmaceuticals were in the range 97.2–104.0%. The results were compared with those obtained with methanol–water mobile phases.

Chapter 63 Assaying Protein Phosphatases in Sperm and Flagella

Sperm and flagellar motility mechanism depends on protein phosphorylation. Dynein has been indicated as a potential site of convergence for regulation through phosphorylation/dephosphorylation by protein kinases and phosphatases. Phosphorylation of dynein has been correlated with increased ATPase activity and an increase in the velocity of dynein-mediated gliding of microtubules in vitro. An important role for protein phosphatases in motility regulation has been suggested by adding protein phosphatases or their inhibitors to flagellar models. A significant decrease in the gliding velocity of microtubules in vitro by dynein has been observed by preincubation of dynein with serinekhreonine protein phosphatase, SPP, recently purified from sea urchin sperm. The enzyme specifically dephosphorylates a single dynein-associated subunit phosphorylated by cyclic adenosine monophosphate (cAMP)-dependent protein kinase. This chapter describes the assay for serine/threonine protein phosphatases using the dephosphorylation of type II regulatory subunit (RII) peptide phosphorylated by cAMP-dependent protein kinase as substrate and the considerations when designing experiments to examine the effect of protein phosphatases and kinases on the gliding velocity of microtubules in vitro by dynein. The methods presented are purification of the catalytic subunit of cAMP-dependent protein kinase, phosphorylation and purification of RII substrate, and protein phosphatase assay. The ability to assay dynein function by examining the propulsion of taxol-stabilized microtubules on glass surfaces offers a tool for examining the role of protein phosphorylation. All experiments examining effects on gliding of manipulation in solution are conducted in parallel with incubations using dynein that has been treated with [ 32 P]ATP and analyzed by sodium dodecyl phosphate–polyacrylamide gel electrophoresis (SDS-PAGE) and autoradiography, to confirm changes in protein phosphorylation that are associated with changes in gliding velocity. A peptide substrate radiolabeled to a high specific activity is essential for the high sensitivity and reproducibility of the protein phosphatase activity.

Electrical Aspects of Adsorbing Colloid Flotation. XXI. Flotation with Dodecylphosphate/n-Hexanol Mixtures

Abstract The adsorbing colloid flotation of Pb(II), Cd(II), and Cu(II) with ferric hydroxide floc and the mixed surfactant system sodium dodecylphosphate (SDP)/n-hexanol was investigated. Good removals of Pb and Cu were obtained; removal of Cd was less satisfactory. The effects of interfering anions (sulfate, oxalate, silicate, phosphate) were studied; higher concentrations of these ions could be tolerated with SDP/n-hexanol than with sodium dodecylsulfate. Measurements of the cmc of SDP were made; low solubility prevented determinations in the pH range 4–8.5.

Electrical Aspects of Adsorbing Colloid Flotation. XIX. Viscosity and the Structures of Mixed Micelles

Abstract Viscosity measurements on mixed surfactant solutions containing the nonionic surfactant Triton X-100 and a number of other cosurfactants (dodecanoic acid, dodecyl amine, sodium dodecylsulfate, dodecyltrimethylammonium chloride, dodecyl alcohol, and sodium dodecylphosphate) indicate the presence of two quite different ‘types of micelles’. Solutions containing an electrically neutral cosurfactant exhibit very large viscosities, indicating the presence of extended micellar structures. Solutions containing a charged cosurfactant exhibit much lower viscosities, indicating that the micelles in these solutions are small spherical or ellipsoidal structures. Evidently coulombic repulsions destabilize the extended structures when charged surfactants are present in the micelles. The effects of pH and ionic strength are consistent with this interpretation.