ACE applied to the quantitative characterization of benzo‐18‐crown‐6‐ether binding with alkali metal ions in a methanol–water solvent system

Ehala, Sille; Makrlík, Emanuel; Toman, Petr; Kašička, Václav

doi:10.1002/elps.200900581

Cited by 34 publications

(23 citation statements)

References 46 publications

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“…Molar conductivity was introduced as a function of the square root of Bu 4 N + F − concentration for a strong 1:1 electrolyte according to Eq. by the Debye–Hückel–Onsager (DHO) model .

Λ = Λ^{\infty} - (A Λ^{\infty} + B) c^{1 / 2}

and, A = 0.818 \times 10^{6} / {((), ɛ T)}^{3 / 2}

B = 82 / η {(ɛ T)}^{1 / 2}

where Λ ∞ is the molar conductivity of the electrolyte in S⋅cm 2 ⋅L⋅mol −1 at infinite dilution, ε is the relative permittivity, η is the viscosity in 10 −1 Pa⋅s, and T is the absolute temperature.…”

Section: Resultsmentioning

confidence: 99%

Effects of ion pairing on the capillary electrophoretic separation and ultraviolet‐absorption detection of quaternary ammonium cations using meso‐octamethylcalix[4]pyrrole as the background electrolyte additive

Luo

Ma²,

2015

J of Separation Science

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Five quaternary ammonium cations, including tetramethylammonium, tetraethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, and 1-butyl-3-methylimidazolium, have been separated by capillary electrophoresis. A direct ultraviolet method has been achieved when tetrabutylammonium fluoride was the background electrolyte and meso-octamethylcalix[4]pyrrole was the background electrolyte additive. The ultraviolet spectra of meso-octamethylcalix[4]pyrrole and cation mixtures showed that redshifts can be attributed to the size of cations, and the maximum absorption wavelength shifted from 218 to 230 nm when tetrabutylammonium cation was substituted with tetramethylammonium cation or tetraethylammonium cation. Conductivity measurements were performed to evaluate the ion-pairing effect of tetrabutylammonium fluoride in a mixture of acetonitrile/ethanol (80:20, v/v), and the ion-pairing formation constant, Kip, was calculated (Kip = 14.8 ± 0.3 L/mol) using the Fuoss extended model. Ion pairing also occurs between cations of the analytes and counterion, a fluoride complex of meso-octamethylcalix[4]pyrrole. The tetramethylammonium cations associate more strongly with this counterion than the tetraethylammonium cation that contributes to the change of selectivity in capillary electrophoresis separation. The effective mobilities of the cations with trimethyl groups, such as tetramethylammonium cation, benzyltrimethylammonium cation, and hexadecyltrimethylammonium cation, decreased faster than others with the increase of meso-octamethylcalix[4]pyrrole concentration, highlighting the fact that the ion-pairing effect played an important role in this method.

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“…Molar conductivity was introduced as a function of the square root of Bu 4 N + F − concentration for a strong 1:1 electrolyte according to Eq. by the Debye–Hückel–Onsager (DHO) model .

Λ = Λ^{\infty} - (A Λ^{\infty} + B) c^{1 / 2}

and, A = 0.818 \times 10^{6} / {((), ɛ T)}^{3 / 2}

B = 82 / η {(ɛ T)}^{1 / 2}

Section: Resultsmentioning

confidence: 99%

Effects of ion pairing on the capillary electrophoretic separation and ultraviolet‐absorption detection of quaternary ammonium cations using meso‐octamethylcalix[4]pyrrole as the background electrolyte additive

Luo

Ma²,

2015

J of Separation Science

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“…Same to the other metal ions or metal compounds, organotin compounds could achieve equilibrium within the ACE separation time [22,23]. Usually, the interaction between drugs and biomolecules could be considered as 1:1 molar ratio in CE analysis [24][25][26]. Comparing to the organotin compound concentration, the maximum protein concentration is not high.…”

Section: Resultsmentioning

confidence: 99%

Characterization of interactions between organotin compounds and human serum albumin by capillary electrophoresis coupled with inductively coupled plasma mass spectrometry

Sun

Liu

et al. 2012

Talanta

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Inductively coupled plasma mass spectrometry Human serum albumin Affinity capillary electrophoresis Nonequilibrium capillary electrophoresis assays of equilibrium mixtures assays a b s t r a c t Thermodynamic data such as the binding constants are vital parameters describing interactions between exotic trace compounds and biomolecules in biochemical property modeling. In this study, the stability constants of organometallic compound and protein complexes were studied by using capillary electrophoresis coupled with inductively coupled plasma mass spectrometry (CE-ICP-MS), considering its low detection limits and low sample demand. Four organotin compounds (trimethyltin (TMT), tripropyltin (TPrT), tributyltin (TBT), triphenyltin (TPhT)) and human serum albumin (HSA) were used as model organometallic compounds and protein, respectively. Affinity capillary electrophoresis (ACE) and nonequilibrium capillary electrophoresis assays of equilibrium mixtures (NECEEM) were performed and compared by using ICP-MS as the detector to determine the binding constants of organotin compounds and HSA in 1:1 molar ratio assumption. Constant measurements of the two methods were both simple, however, ACE assays were more accurate and more appropriate for the constant determination of the organotin-HSA complexes, considering the errors of the NECEEM method. A good precision of the binding constants (log K b ) using the ACE method was proved by different mathematical calculations, and the values were 6.13 ± 0.51 (TMT), 5.72 ± 0.38 (TPrT), 5.68 ± 0.34 (TBT), 6.05 ± 0.38 (TPhT) respectively for each of the organotin-HSA complexes, showing non-covalent interaction between organotin compounds and HSA. Meanwhile, this study also confirms the suitability of CE-ICP-MS method for further studies on organometallic complexation.

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“…Corrections of the measured electrophoretic mobilities of different analytes for constant BGE ionic strength are mostly performed by using the extended Debye, Hückel and Onsager theory introduced by Falkenhagen et al. and Pitts as shown in several papers .…”

Section: Introductionmentioning

confidence: 99%

Determination of binding constants of multiple charged cyclodextrin complexes by ACE using uncorrected and ionic strength corrected actual mobilities of the species involved

et al. 2019

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Determination of binding constants of multiple charged cyclodextrin complexes by ACE using uncorrected and ionic strength corrected actual mobilities of the species involvedIn this study, the apparent binding constants and limiting mobilities of the multiply charged complexes of the − and −enantiomers of Ru(II)-and Fe(II)-polypyridyl associates ([Ru(2,2 -bipyridine) 3 ] 2+ , [Ru(1,10-phenanthroline) 3 ] 2+ , and [Fe(1,10phenanthroline) 3 ] 2+ ) with single-isomer 2,3-diacetylated-6-sulfated-cyclodextrins (CDs) (12Ac-6S-α-CD, 14Ac-7S-β-CD, and 16Ac-8S-γ-CD) were determined by ACE using uncorrected and ionic strength corrected actual mobilities of the species involved. Two limiting models were tested for the ionic strength correction of the actual mobilities based on an empirical relation for the ionic strength correction of multivalent ionic species. In model 1, the nominal values of the charge numbers (z S,nom ) and analytical concentrations (c S,nom ) of the above CD selectors in the BGEs were applied for calculation of the BGE ionic strength, as usual. In model 2, the CD selectors were considered as singly charged species (z S = −1) with |z S,nom |-times higher concentrations in the BGE than their analytical concentrations (c S = |z S,nom | × c S,nom ) in the calculation of the BGE ionic strength. In all three cases-with uncorrected actual mobilities as well as with actual mobilities corrected according to the two limiting models-the measured effective mobilities of the above enantiomers fit well the theoretical curves of their mobility dependences on the CD selectors concentrations in the BGE, with high average coefficients of determination (R 2 = 0.9890-0.9995). Nevertheless, the best physico-chemically meaningful values of the apparent binding constants and the limiting mobilities of the enantiomer-CDs complexes with low RSDs were obtained using the actual mobilities of the species involved corrected according to model 2.

show abstract

ACE applied to the quantitative characterization of benzo‐18‐crown‐6‐ether binding with alkali metal ions in a methanol–water solvent system

Cited by 34 publications

References 46 publications

Effects of ion pairing on the capillary electrophoretic separation and ultraviolet‐absorption detection of quaternary ammonium cations using meso‐octamethylcalix[4]pyrrole as the background electrolyte additive

Effects of ion pairing on the capillary electrophoretic separation and ultraviolet‐absorption detection of quaternary ammonium cations using meso‐octamethylcalix[4]pyrrole as the background electrolyte additive

Characterization of interactions between organotin compounds and human serum albumin by capillary electrophoresis coupled with inductively coupled plasma mass spectrometry

Determination of binding constants of multiple charged cyclodextrin complexes by ACE using uncorrected and ionic strength corrected actual mobilities of the species involved

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