Effect of formamide and other organic polar solvents on the micelle formation of sodium dodecyl sulfate

Almgren, Mats; Swarup, Shanti; Loefroth, Jan Erik

doi:10.1021/j100267a042

Cited by 83 publications

(43 citation statements)

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“…In other words, addition of FA at concentrations between 22.0 and 32.6% shifts the CMC to the SDS concentration of the present MEKC system, namely to about 10 mM. This finding seems in contrast to that reported by Almgren et al, which demonstrated that a stabilization of SDS micelles takes place in the presence of FA [7]. However, the decisive difference between these results and our present ones lies in the ionic strength of the solutions.…”

Section: Retention Factorscontrasting

confidence: 99%

“…The pure solvent was applied in MEKC by Lin et al [6] with SDS, diethylhexyl sodium sulfosuccinate and sodium taurodeoxycholate as surfactants. This solvent is also exceptional as -in the absence of an electrolyte -the CMC of SDS decreases with increasing FA concentrations in the mixed aqueousorganic solvent from 8 mM in pure water to about 0.4 mM at an FA weight fraction of about 0.7 (then the CMC is increased by addition of FA) [7]. A well-known fact should be mentioned in this context, namely that the electrolyte concentration plays a decisive role for the CMC.…”

Section: Application Of Organic Modifiers In Mekcmentioning

confidence: 99%

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Formamide as an organic modifier in MEKC with SDS

Téllez

Kenndler

2009

Electrophoresis

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The effect of formamide (FA) as a modifier on the retention in MEKC with SDS as the detergent was investigated. The mobility of a series of alkylphenones and of a zwitterionic fluorescent compound as a function of the FA and the SDS concentration was determined for this purpose. Buffering electrolyte was borate, pH 9.23, with total ionic strength of 50 mM. The dependence of the mobility on the FA content - up to 63% w/w - of the BGE (at 10 mM SDS) allows the conclusion that the micelles are destabilized, and the CMC is shifted to higher values. In the system containing 33% FA or more no micelles are present anymore, and the retention factors of all compounds tend to zero. In an MEKC system with 27% v/v FA the CMC of SDS is increased from 2.4 mM in the aqueous BGE with the same buffer composition to 9.7 mM, a behavior that is in contrast to electrolyte-free FA-water systems. The partition constants of free analytes and the formation constants of the adduct between analyte and detergent monomer (assuming 1:1 stoichiometry) were derived from the dependence of the mobility on the SDS concentration. In addition, the involved equilibria were extended by that from the distribution of the analyte-monomer adduct between aqueous and micellar phase, and the according partition constants were derived as well. A selective change in the extent of partitioning was observed for the zwitterionic compound. In general, all binding constants were decreased upon addition of FA, though to a different extent. Although the binding constants of the analyte-monomer associate were only slightly influenced, the most pronounced decrease is found for their partitioning into the micelles.

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Section: Retention Factorscontrasting

confidence: 99%

Section: Application Of Organic Modifiers In Mekcmentioning

confidence: 99%

Formamide as an organic modifier in MEKC with SDS

Téllez

Kenndler

2009

Electrophoresis

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“…There has recently been much research dealing with the effects of nonaqueous polar solvents on the formation of cationic micelles (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). Micel!e or liquid crystal formation has been reported to occur in such solvents as hydrazine (3,4), glycerol (5,6), ethylene glycol (7,8), and formamide (9)(10)(11)(12)(13)(14)(15)(16)(17)(18), where all of the aforementioned solvents have high cohesive energy, dielectric constant, and a high degree of hydrogen bonding. Evans and co-workers (19) have indicated that the ability of a solvent to form hydrogen bonds is a necessary condition of micelle formation.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic properties of micellization of sodium dodecyl sulfate in binary mixtures of ethylene glycol with water

Gracie¹,

Turner²,

Palepu³

1996

Can. J. Chem.

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Micellar properties of sodium dodecyl sulfate (SDS) in aqueous mixtures of ethylene glycol (EG) were determined using techniques such as conductivity, density, EMF, surface tension, viscosity, ultrasonic velocity, and spectroscopy (fluorescence). The effective degree of disssociation of micelles ( a ) was determined using three different methods. Thermodynamics of micellization were obtained from the temperature dependence of critical micelle concentrations (cmc) values. The difference in Gibbs energies of micellization ( A G~) of SDS, between water and mixed solvent systems, was calculated to evaluate the influence of cosolvent on the micellization process. Surfactant aggregation numbers (N,) obtained from static fluorescence quenching methods indicated a decrease in the aggregation numbers with increasing concentration of ethylene glycol in the binary solvent mixtures. In addition, the micropolarity of the micellar interior was determined from the pyrene I,II:, ratios. These values were consistent with a decrease in the micropolarity surrounding the probe molecule as the EG content in the solvent mixture was increased.

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“…For instance, using different organic polar cosolvents, Almgren and Swarup 38 showed that the apparent aggregation number of SDS micelles was reduced as cosolvent concentration increased. Lal and Hakem, 39 using small-angle neutron scattering, showed that PEO had an unusual expansion of its chain in water/AN mixtures (0.49-0.59% D 2 O) compared with that observed in the pure solvents.…”

Section: Effects Of the Cosolvents On Sds And Dss Micellizationmentioning

confidence: 99%

Effect of Acetonitrile and N,N-Dimethylformamide on the Formation of Poly(ethylene oxide)-Sodium Alkyl Sulfate Aggregates

Ferreira

Silva

et al. 2017

J. Braz. Chem. Soc.

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The effects of low contents of acetonitrile (AN) or N,N-dimethylformamide (DMF) on the aggregation of sodium alkyl sulfate surfactants, in the absence and presence of poly(ethylene oxide) (PEO), were investigated using conductivity and isothermal titration calorimetry. The cosolvents slightly changed the critical micellar concentrations and did not alter the critical aggregation concentrations of the surfactants sodium decyl sulfate (DSS) and sodium dodecyl sulfate (SDS) with PEO. However, AN and DMF turned the micellization of the surfactants and their binding to the polymer enthalpically more favorable. For instance, for SDS, the micellization enthalpy, , decreased from close to 0 kJ mol -1 in water to −14.3 kJ mol -1 in the presence of 2.50 mol% AN, and the integral enthalpy change for aggregate formation with the polymer, ΔH agg (int), decreased from −1.1 kJ mol -1 in water to −15.5 kJ mol -1 in the same AN concentration. This was attributed to the modification of the solvation shells of both SDS and PEO by the cosolvent molecules, which reduced the entropic contribution to formation of the aggregates. Consequently, when SDS was replaced with DSS, the AN affected to a lesser extent, with a decrease of 9.1 kJ mol -1 , while the ΔH agg (int) values were not altered, highlighting the influence of hydrophobic interactions in the surfactant aggregation process.

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Effect of formamide and other organic polar solvents on the micelle formation of sodium dodecyl sulfate

Cited by 83 publications

References 0 publications

Formamide as an organic modifier in MEKC with SDS

Formamide as an organic modifier in MEKC with SDS

Thermodynamic properties of micellization of sodium dodecyl sulfate in binary mixtures of ethylene glycol with water

Effect of Acetonitrile and N,N-Dimethylformamide on the Formation of Poly(ethylene oxide)-Sodium Alkyl Sulfate Aggregates

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