Congeneric Behavior in Estimations of Octanol−Water Partition Coefficients by Micellar Electrokinetic Chromatography

Trone, Mark D.; Leonard, Michael S.; Khaledi, Morteza G.

doi:10.1021/ac990852l

Cited by 72 publications

(41 citation statements)

References 41 publications

(56 reference statements)

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“…The water molecules in palisade and Stern layers of the micelles are believed to be responsible for the hydrogen bond donating properties of the micelles. It has been shown that water can penetrate as far as the second or third methylene unit (from the head group) of the surfactant tail in micelles [29][30][31]. The hydrocarbon tail is also believed to influence the amount of water in the palisade and Stern layer.…”

Section: Effect Of Hydrocarbon Chain Length On Hydrogen Bondingmentioning

confidence: 99%

Polymeric sulfated surfactants with varied hydrocarbon tail: II. Chemical selectivity in micellar electrokinetic chromatography using linear solvation energy relationships study

Akbay

Shamsi

2004

Electrophoresis

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The effect of hydrocarbon chain length on chemical selectivity in micellar electrokinetic chromatography (MEKC) was investigated using polymeric sulfated surfactants: poly-(sodium 7-octenyl sulfate), poly(sodium 8-nonenyl sulfate), poly(sodium 9-decenyl sulfate), and poly(sodium 10-undecenyl sulfate). Linear solvation energy relationships (LSERs) and free energy of transfer studies were conducted to predict the selectivity differences between the four polymeric surfactants. The overall nature of the solute/ polymeric micelle interactions was found to be different despite the fact that all polymeric surfactants have the same head group. The polar character and acidic strength of the polymeric surfactant are found to decrease as the hydrocarbon chain length of the surfactant is increased. On the other hand, the polarizability of the polymeric sulfated surfactants increases (upon interacting with solute lone-pair electrons) with increasing hydrocarbon chain length. The LSER results show that the solute size and hydrogen bond accepting ability play the key roles in MEKC retention.

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Section: Effect Of Hydrocarbon Chain Length On Hydrogen Bondingmentioning

confidence: 99%

Polymeric sulfated surfactants with varied hydrocarbon tail: II. Chemical selectivity in micellar electrokinetic chromatography using linear solvation energy relationships study

Akbay

Shamsi

2004

Electrophoresis

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“…The correlation between retention data in MEKC and the octanol-water partition coefficient log P OW was studied by several authors: a linear correlation of log k on log P OW as well as RI on log P OW can be established within analyte classes, showing similar changes in the free energy of phase transfer in the two biphasic systems octanol-water or micel-lar phase/aqueous phase [2][3][4][6][7][8][9][10]. Different slopes of the regression lines are obtained for different classes of analytes (neutral nonpolar analytes without hydrogen bond donator or acceptor properties, hydrogen bond donators, and hydrogen bond acceptors) [2,7,10].…”

Section: Introductionmentioning

confidence: 99%

Separation of very hydrophobic analytes by MEKC. II. Carbon number equivalents as analyte descriptors – influence of the composition of the separation electrolyte

2008

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The use of the parameter carbon number equivalent, N(c)(*), as analyte descriptor for neutral hydrophobic solutes in EKC is investigated. The carbon number equivalent of an analyte is defined analogously to the retention index, RI, however, it is directly calculated from the regression line plotting for the members of a homologous series the logarithm of the retention factor against the number of methylene units N(c) in the alkyl chain. This plot can be obtained by using simultaneously an iteration procedure for the calculation of t(MC). For separation electrolytes containing SDS as micellar phase employing ACN, urea, and CaCl(2) as additives within a wide span of concentrations the parameter N(c)(*) is quasi-independent of the composition of the separation electrolyte, being of importance concerning identification of analytes and improving repeatability and reproducibility. With known octanol-water partition coefficients for the members of the homologous series taken as reference it is possible to transform the conventional time scale of an electropherogram into a scale of N(c)(*) or a scale of log P(OW). Due to the quasi-independence of N(c)(*) from the composition of the separation electrolyte these transformed electropherograms can be used as normalized electropherograms for identification purposes. It is also shown that the linear dependence of log P(OW) on N(c) can be the basis of the determination of octanol-water partition coefficients of solutes within a very large range (-4 < or = log P(OW) < or = 9).

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“…It was based on the retention of betamethasone and its derivatives expressed by log k i and log P OW as a measure to estimate hydrophobicity, as done by a number of authors (see, e.g., [26,[28][29][30][31]). MEKC systems consist either from SDS, or from bile acids as micelle formers.…”

Section: Introductionmentioning

confidence: 99%

Comparison of the retention characteristics of different pseudostationary phases for microemulsion and micellar electrokinetic chromatography of betamethasone and derivatives

Lucangioli¹,

Carducci²,

Scioscia³

et al. 2003

Electrophoresis

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Five electrokinetic chromatography systems were compared concerning retention behavior and lipophilicity. Comparison was based on capacity (retention) factors of some steroidal drugs, and on log P(OW) values derived by the aid of reference substances. In all systems the aqueous buffer consisted of phosphate (20 mM, pH 7.5). Two systems had micelles, three systems microdroplets as negatively charged pseudostationary phases. The micelles were formed by sodium dodecyl sulfate (SDS) and sodium cholate, respectively. One microemulsion consisted (as usual) from octane as oil, butanol as cosurfactant and SDS as charged tenside. Two microemulsions were made from biosurfactants (phosphatidylcholine, isopropylmyristate) to better simulate biopartitioning of the drugs. Even for noncharged analytes a change in migration sequence and thus in log P(OW) was observed for the systems consisting of the biosurfactants, compared to the others. For the former systems, log P(OW) derived from the capacity factors agree for all analytes with those obtained from calculation by computer software based on the structure of the drugs, and with experimental data directly obtained from octanol/water partitioning.

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Congeneric Behavior in Estimations of Octanol−Water Partition Coefficients by Micellar Electrokinetic Chromatography

Cited by 72 publications

References 41 publications

Polymeric sulfated surfactants with varied hydrocarbon tail: II. Chemical selectivity in micellar electrokinetic chromatography using linear solvation energy relationships study

Polymeric sulfated surfactants with varied hydrocarbon tail: II. Chemical selectivity in micellar electrokinetic chromatography using linear solvation energy relationships study

Separation of very hydrophobic analytes by MEKC. II. Carbon number equivalents as analyte descriptors – influence of the composition of the separation electrolyte

Comparison of the retention characteristics of different pseudostationary phases for microemulsion and micellar electrokinetic chromatography of betamethasone and derivatives

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