Binding of calcium ions to micelles ? a metallochromic indicator study

Miller, Daniel J.

doi:10.1007/bf01410342

Cited by 10 publications

(8 citation statements)

References 19 publications

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“…Since each exp(-kA WNr) is independent, the terms for N' = "'must be equal SO C N N~ (-kAWN + kAW") = C N -I N ,~A~-' , or (43) From eq 41, COO = 1 and CNN = -z~;~O~IYNp, so eq 43 generates all of the coefficients in eq 40 which determines PN(t). The rate at which additives adhere is k,C;=,P,(t)@.…”

Section: Appendix B a Physically Intuitive Modelmentioning

confidence: 98%

Statistical distributions and collision rates of additive molecules in compartmentalized liquids studied by EPR spectroscopy. 1. Sodium dodecyl sulfate micelles, 5-doxylstearic acid ester, and cobalt(II)

Bales¹,

Stenland²

1993

J. Phys. Chem.

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A technique to study the statistical distribution and collision rates of additive molecules in compartmentalized liquids is developed and applied to C O ( H~O )~~+ in SDS micelles. The physical model employs a dilute solution of a nitroxide free radical, the indicator, in the presence and absence of a varying concentration of paramagnetic molecules, the broadeners, which are C O ( H~O )~~+ in this case. The EPR spectra of the indicator vary nonlinearly with the concentration of the broadener in a manner consistent with a hypothesis that the resident time of a CO(H~O)~*+ ion on one micelle is long compared with lO-'s but inconsistent with a random distribution of the added divalent cations among the micelles. A simple theory is developed which takes into account interactions between broadeners residing in the same compartment and ignores such interactions if they reside in different compartments. Assuming a small electrostatic repulsion between the cations brings the experimental results into agreement with theory and allows the collision rate of the broadener with the indicator to be estimated. For C O ( H~O )~~+ ,this collision rate decreases linearly as a function of the inverse volume of the micelle as predicted by a simple random walk model. The polarity of SDS micelles, as estimated by the I4N hyperfine coupling constant of the indicator, decreases linearly with micelle size, while the microviscosity, as estimated from the rotational correlation time of the indicator, increases linearly with this size.

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Section: Appendix B a Physically Intuitive Modelmentioning

confidence: 98%

Statistical distributions and collision rates of additive molecules in compartmentalized liquids studied by EPR spectroscopy. 1. Sodium dodecyl sulfate micelles, 5-doxylstearic acid ester, and cobalt(II)

Bales¹,

Stenland²

1993

J. Phys. Chem.

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“…4,5 The free ion concentrations can be measured using electrochemical probes [5][6][7] or fluorescent dyes. [8][9][10] However, such measurements can be expensive and inconvenient to perform in addition to NMR, particularly when only limited quantities of sample are available. Furthermore, the insertion of electrodes can cause serious damage to soft-solid samples such as gels while electrochemical methods are also wholly unsuited to study the internal ion gradients that can occur in these systems.…”

mentioning

confidence: 99%

“…When complexing species are present, the concentration of free ions can be very different to the total concentrations of Ca or Mg. The free ion concentrations thus grant valuable insight into the ion-responsive behavior of the systems. , The free ion concentrations can be measured using electrochemical probes − or fluorescent dyes. − However, such measurements can be expensive and inconvenient to perform in addition to NMR, particularly when only limited quantities of sample are available. Furthermore, the insertion of electrodes can cause serious damage to soft-solid samples such as gels while electrochemical methods are also wholly unsuited to study the internal ion gradients that can occur in these systems. , Methods for the direct measurement of free Ca 2+ and Mg 2+ concentrations by NMR are thus required.…”

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confidence: 99%

Self-Correcting Method for the Measurement of Free Calcium and Magnesium Concentrations by ¹H NMR

et al. 2019

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A method for the direct measurement of free Ca2+ and Mg2+ concentrations in the range of 1–100 mM by NMR spectroscopy is demonstrated. The method automatically corrects for the effect of ionic strength on the activity of the species in solution and works satisfactorily even when significant concentrations of competitive ions are present. The method requires only the measurement of the 1H chemical shifts of our reporter ligands, glycolate and sulfoacetate, and is easily implemented using NMR imaging techniques. As a proof of concept, we extract the thermodynamic binding constants and conformer distributions of analyte ligands using an in situ ion gradient. Existing approaches for the measurement of free Ca2+ or Mg2+ concentrations by NMR operate only at very low ion concentrations or else require careful recalibration for different sample conditions. By providing the free Ca2+ or Mg2+ concentrations, the proposed methodology significantly enhances the information obtainable via NMR investigations of ion-responsive systems.

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“…Fan et al [113] and Miller [114] considered the micelle surface to have discrete exchange sites and defined the exchange of Na + with Ca 2+ on anionic micelles through the following ion exchange-like equilibrium equation with equilibrium constant β,…”

Section: Figurementioning

confidence: 99%

Inorganic anion removal using micellar enhanced ultrafiltration (MEUF), modeling anion distribution and suggested improvements of MEUF: A review

Chen

Jafvert

et al. 2020

Chemical Engineering Journal

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Surfactants have been used often in environmental remediation strategies due to their special amphiphilic nature which alters surface and water interfacial properties. When the aqueous concentration of a cationic surfactant far exceeds the critical micelle concentration (CMC), a large concentration of cationic micelles will form in water. These micelles each consist of tens to hundreds of surfactant monomers, and collectively can be utilized as nano-sized ion exchangers to assist with ultrafiltration separation (i.e., removal) of anionic pollutants from natural waters or wastewaters. Target anionic pollutants include nitrate, phosphate, arsenate and chromate. However, most polluted waters contain a complex mixture of anions, with these different anions competing for the micellar pseudo-phase, thus potentially reducing the overall removal efficiency of the target anions.Further, loss of surfactant monomers through the membrane also reduces process efficiency as replenishment of surfactant over time is required. In this review, the existing research on inorganic anion removal by micellar enhanced ultrafiltration (MEUF) and similar processes

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Binding of calcium ions to micelles ? a metallochromic indicator study

Cited by 10 publications

References 19 publications

Statistical distributions and collision rates of additive molecules in compartmentalized liquids studied by EPR spectroscopy. 1. Sodium dodecyl sulfate micelles, 5-doxylstearic acid ester, and cobalt(II)

Statistical distributions and collision rates of additive molecules in compartmentalized liquids studied by EPR spectroscopy. 1. Sodium dodecyl sulfate micelles, 5-doxylstearic acid ester, and cobalt(II)

Self-Correcting Method for the Measurement of Free Calcium and Magnesium Concentrations by ¹H NMR

Inorganic anion removal using micellar enhanced ultrafiltration (MEUF), modeling anion distribution and suggested improvements of MEUF: A review

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Binding of calcium ions to micelles ? a metallochromic indicator study

Cited by 10 publications

References 19 publications

Statistical distributions and collision rates of additive molecules in compartmentalized liquids studied by EPR spectroscopy. 1. Sodium dodecyl sulfate micelles, 5-doxylstearic acid ester, and cobalt(II)

Statistical distributions and collision rates of additive molecules in compartmentalized liquids studied by EPR spectroscopy. 1. Sodium dodecyl sulfate micelles, 5-doxylstearic acid ester, and cobalt(II)

Self-Correcting Method for the Measurement of Free Calcium and Magnesium Concentrations by 1H NMR

Inorganic anion removal using micellar enhanced ultrafiltration (MEUF), modeling anion distribution and suggested improvements of MEUF: A review

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Self-Correcting Method for the Measurement of Free Calcium and Magnesium Concentrations by ¹H NMR