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G B Dutt - One of the best experts on this subject based on the ideXlab platform.
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Rotational Diffusion of Charged and Nondipolar Solutes in Ionic Liquid–Organic Solvent Mixtures: Evidence for Stronger Specific Solute–Solvent Interactions in Presence of Organic Solvent
2015Co-Authors: Sugosh R. Prabhu, G B DuttAbstract:Rotational diffusion of a charged solute, Rhodamine 110 (R110), and a nondipolar solute, 2,5-dimethyl-1,4-dioxo-3,6-diphenylpyrrolo[3,4-c]pyrrole (DMDPP), has been investigated in ionic liquids, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][Tf2N]) and 1-butyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([BMIM][FAP]), with 0.8 mole fraction of dibenzyl ether (DBE). This study has been undertaken to find out how specific interactions between the solute and the ionic liquid are affected upon dilution with a nondipolar solvent. It has been observed that at a given viscosity (η) and temperature (T), the reorientation times of R110 increase by 40–60% in the ionic liquid–organic solvent mixtures compared to ones in the corresponding neat ionic liquids. In the case of DMDPP, the influence of DBE is less pronounced, and its reorientation times increase by 25–50% at a given η/T. The addition of DBE weakens the numerous interactions prevailing between the cations and the anions of the ionic liquids, which results in stronger specific interactions between the solutes and the constituent ions, consequently leading to slower rotation of the solutes
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can critical packing parameter depict probe rotation in block copolymer reverse micelles
Journal of Physical Chemistry B, 2013Co-Authors: Sugoshr Prabhu, G B DuttAbstract:Rotational diffusion of two ionic probes, cationic Rhodamine 110 (R110) and anionic fluorescein (FL), has been examined in reverse micelles formed with the triblock copolymer (EO)13–(PO)30–(EO)13 (L64), where EO and PO represent ethylene oxide and propylene oxide units, respectively, with small amounts of water in p-xylene. This study has essentially been undertaken to explore the influence of mole ratio of water to copolymer (W) as well as copolymer concentration on probe rotation. On the basis of fluorescence lifetimes and reorientation times, it has been established that both R110 and FL are located in the interfacial region of L64/water/p-xylene reverse micellar system. The average reorientation time decreases by 10–35% with an increase in W for both the probes at a given copolymer concentration. However, for a particular W, the average reorientation time increases by 10–30% as the concentration of the copolymer is enhanced. From the micellar structural parameters available in the literature, critical...
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can critical packing parameter depict probe rotation in block copolymer reverse micelles
Journal of Physical Chemistry B, 2013Co-Authors: Sugoshr Prabhu, G B DuttAbstract:Rotational diffusion of two ionic probes, cationic Rhodamine 110 (R110) and anionic fluorescein (FL), has been examined in reverse micelles formed with the triblock copolymer (EO)13–(PO)30–(EO)13 (L64), where EO and PO represent ethylene oxide and propylene oxide units, respectively, with small amounts of water in p-xylene. This study has essentially been undertaken to explore the influence of mole ratio of water to copolymer (W) as well as copolymer concentration on probe rotation. On the basis of fluorescence lifetimes and reorientation times, it has been established that both R110 and FL are located in the interfacial region of L64/water/p-xylene reverse micellar system. The average reorientation time decreases by 10–35% with an increase in W for both the probes at a given copolymer concentration. However, for a particular W, the average reorientation time increases by 10–30% as the concentration of the copolymer is enhanced. From the micellar structural parameters available in the literature, critical...
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can critical packing parameter depict probe rotation in block copolymer reverse micelles b
The Journal of Physical Chemistry, 2013Co-Authors: Sugoshr Prabhu, G B DuttAbstract:Rotational diffusion of two ionic probes, cationic Rhodamine 110 (R110) and anionic fluorescein (FL), has been examined in reverse micelles formed with the triblock copolymer (EO)₁₃–(PO)₃₀–(EO)₁₃ (L64), where EO and PO represent ethylene oxide and propylene oxide units, respectively, with small amounts of water in p-xylene. This study has essentially been undertaken to explore the influence of mole ratio of water to copolymer (W) as well as copolymer concentration on probe rotation. On the basis of fluorescence lifetimes and reorientation times, it has been established that both R110 and FL are located in the interfacial region of L64/water/p-xylene reverse micellar system. The average reorientation time decreases by 10–35% with an increase in W for both the probes at a given copolymer concentration. However, for a particular W, the average reorientation time increases by 10–30% as the concentration of the copolymer is enhanced. From the micellar structural parameters available in the literature, critical packing parameters have been calculated for the L64/water/p-xylene reverse micellar system, and it has been noticed that the average reorientation times of both the probes scale linearly with the critical packing parameter. In essence, the results of this study indicate that the probe mobility in the interfacial region of block copolymer reverse micelles is governed by the micellar packing.
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fluorescence anisotropy of ionic probes in aot reverse micelles influence of water droplet size and electrostatic interactions on probe dynamics
Journal of Physical Chemistry B, 2008Co-Authors: G B DuttAbstract:Fluorescence anisotropies of two structurally similar ionic probes, Rhodamine 110 and fluorescein, were measured in di(2-ethylhexyl) sodium sulfosuccinate (AOT) reverse micelles as a function of the mole ratio of water to surfactant W. This study was undertaken to explore the influence of water droplet size and electrostatic interactions on the rotational diffusion of the probe molecules. It was noticed that at W = 1 and 2, the anisotropy decays of both the probes display single-exponential behavior and for a particular value of W, the time constants sensed by Rhodamine 110 and fluorescein are identical. Moreover, an increase in the reorientation time was observed from W = 1 to 2. These observations indicate that, at W = 1 and 2, it is the overall rotation of micelle which is responsible for the decay of the anisotropy and also rule out the possibility of internal rotation of the probes within the reverse micelles. However, from W = 4 to 20, the anisotropy decays of the probes could only be described by a biexponential function with two time constants. The rotational diffusion of Rhodamine 110 and fluorescein in the above-mentioned range of W was rationalized using the two-step model. The average reorientation time decreases with an increase in W for both the probes, and this decrease is pronounced in the case of fluorescein compared to that in Rhodamine 110. The decrease in the average reorientation time with W is due to the change in the micellar packing within the core. The significant reduction in the average reorientation time of fluorescein is a consequence of repulsive electrostatic interactions between the negatively charged probe and the anionic head groups of the surfactant AOT.
Jagdish P Singh - One of the best experts on this subject based on the ideXlab platform.
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modulated optical phase conjugation in Rhodamine 110 doped boric acid glass saturable absorber thin films
Applied Physics Letters, 2008Co-Authors: Ramesh C Sharma, Thomas A Waigh, Jagdish P SinghAbstract:The optical phase conjugation signal in nearly nondegenerate four wave mixing was studied using a Rhodamine 110 doped boric acid glass saturable absorber nonlinear medium. We have demonstrated a narrow band optical filter (2.56±0.15Hz) using an optical phase conjugation signal in the frequency modulation of a weak probe beam in the presence of two strong counterpropagating pump beams in Rhodamine 110 doped boric acid glass thin films (10−4m). Both the pump beams and the probe beam are at a wavelength of 488nm (continuous-wave Ar+ laser). The probe beam frequency was detuned with a ramp signal using a piezoelectric transducer mirror.
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two coherent wave coupling in Rhodamine 110 doped boric acid glass solid films
Journal of The Optical Society of America B-optical Physics, 2007Co-Authors: Ramesh C Sharma, Anjan Barman, S N Thakur, Jagdish P SinghAbstract:We report the energy-transfer efficiency in a saturable absorber nonlinear media by two-coherent-wave coupling using the Doppler shift. Intensity-dependent nondegenerate two-beam coupling has been studied in Rhodamine 110-doped boric acid glass films. Two beams have been described in the limit of a weak probe and a relatively strong pump at the wavelength 488 nm from a continuous-wave Ar+ laser. The results have been interpreted in terms of the four-level description of a saturable absorber. We obtained good agreement between the experimental and the theoretical results. Estimated values of the nonlinear parameters such as the saturation intensity, refractive index, and the response time of the optical nonlinearity have been obtained at different pump beam intensities for the first time, to our knowledge, in the Rhodamine 110-doped film.
Kevin J Wilkinson - One of the best experts on this subject based on the ideXlab platform.
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diffusion coefficients of several Rhodamine derivatives as determined by pulsed field gradient nuclear magnetic resonance and fluorescence correlation spectroscopy
Journal of Fluorescence, 2008Co-Authors: P O Gendron, Fabrice Avaltroni, Kevin J WilkinsonAbstract:Rhodamine derivatives are popular, photostable fluorophores that are used in a number of fluorescent based techniques, including fluorescence correlation spectroscopy (FCS). Indeed, in FCS, both Rhodamine 6G (R6G) and Rhodamine 110 (R110) are used as calibration standards to determine the dimensions of the instrument confocal volume. In spite of a requirement for precise values of the diffusion coefficients, literature values are scarce and vary over an order of magnitude. In this paper, the diffusion coefficients of four Rhodamine fluorophores (Rhodamine 6G (R6G), Rhodamine B (RB), Rhodamine 123 (R123), Rhodamine 110 (R110)) were determined by pulsed field gradient nuclear magnetic resonance (PFG-NMR) spectrometry and then validated by comparison with fluorescence correlation spectroscopy. With the objective of validating the FCS calibration, diffusion coefficients of several dextrans and a polystyrene nanoparticle were also determined and compared with literature values or theoretical values that were based upon the Stoke-Einstein equation. The work presented here lead us to conclude that the diffusion coefficients for R6G and R110 have generally been underestimated in the literature. We propose revised values of 4.4x10(-10) m2 s(-1) for R110 and 4.0x10(-10) m2 s(-1) for R6G. Using the revised D value for R110 to calibrate the FCS instrument, diffusion coefficients have then been systematically determined for different conditions of pH, ionic strength and concentration. To correct for differences due to solvent effects (D2O vs. H2O), an isotopic correction factor, DD2O/DH2O of 1.23, was determined from both FCS and from the solvent auto-diffusion coefficients obtained by NMR.
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diffusion coefficients of several Rhodamine derivatives as determined by pulsed field gradient nuclear magnetic resonance and fluorescence correlation spectroscopy
Journal of Fluorescence, 2008Co-Authors: P O Gendron, Fabrice Avaltroni, Kevin J WilkinsonAbstract:Rhodamine derivatives are popular, photostable fluorophores that are used in a number of fluorescent based techniques, including fluorescence correlation spectroscopy (FCS). Indeed, in FCS, both Rhodamine 6G (R6G) and Rhodamine 110 (R110) are used as calibration standards to determine the dimensions of the instrument confocal volume. In spite of a requirement for precise values of the diffusion coefficients, literature values are scarce and vary over an order of magnitude. In this paper, the diffusion coefficients of four Rhodamine fluorophores (Rhodamine 6G (R6G), Rhodamine B (RB), Rhodamine 123 (R123), Rhodamine 110 (R110)) were determined by pulsed field gradient nuclear magnetic resonance (PFG-NMR) spectrometry and then validated by comparison with fluorescence correlation spectroscopy. With the objective of validating the FCS calibration, diffusion coefficients of several dextrans and a polystyrene nanoparticle were also determined and compared with literature values or theoretical values that were based upon the Stoke–Einstein equation. The work presented here lead us to conclude that the diffusion coefficients for R6G and R110 have generally been underestimated in the literature. We propose revised values of 4.4 × 10−10 m2 s−1 for R110 and 4.0 × 10−10 m2 s−1 for R6G. Using the revised D value for R110 to calibrate the FCS instrument, diffusion coefficients have then been systematically determined for different conditions of pH, ionic strength and concentration. To correct for differences due to solvent effects (D2O vs. H2O), an isotopic correction factor, \({{D_{{\text{D}}_2 {\text{O}}} } \mathord{\left/ {\vphantom {{D_{{\text{D}}_2 {\text{O}}} } {D_{{\text{H}}_2 {\text{O}}} }}} \right. \kern-\nulldelimiterspace} {D_{{\text{H}}_2 {\text{O}}} }}\) of 1.23, was determined from both FCS and from the solvent auto-diffusion coefficients obtained by NMR.
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diffusion coefficients of several Rhodamine derivatives as determined by pulsed field gradient nuclear magnetic resonance and fluorescence correlation spectroscopy
Journal of Fluorescence, 2008Co-Authors: P O Gendron, Fabrice Avaltroni, Kevin J WilkinsonAbstract:Rhodamine derivatives are popular, photostable fluorophores that are used in a number of fluorescent based techniques, including fluorescence correlation spectroscopy (FCS). Indeed, in FCS, both Rhodamine 6G (R6G) and Rhodamine 110 (R110) are used as calibration standards to determine the dimensions of the instrument confocal volume. In spite of a requirement for precise values of the diffusion coefficients, literature values are scarce and vary over an order of magnitude. In this paper, the diffusion coefficients of four Rhodamine fluorophores (Rhodamine 6G (R6G), Rhodamine B (RB), Rhodamine 123 (R123), Rhodamine 110 (R110)) were determined by pulsed field gradient nuclear magnetic resonance (PFG-NMR) spectrometry and then validated by comparison with fluorescence correlation spectroscopy. With the objective of validating the FCS calibration, diffusion coefficients of several dextrans and a polystyrene nanoparticle were also determined and compared with literature values or theoretical values that were based upon the Stoke–Einstein equation. The work presented here lead us to conclude that the diffusion coefficients for R6G and R110 have generally been underestimated in the literature. We propose revised values of 4.4 × 10−10 m2 s−1 for R110 and 4.0 × 10−10 m2 s−1 for R6G. Using the revised D value for R110 to calibrate the FCS instrument, diffusion coefficients have then been systematically determined for different conditions of pH, ionic strength and concentration. To correct for differences due to solvent effects (D2O vs. H2O), an isotopic correction factor, \({{D_{{\text{D}}_2 {\text{O}}} } \mathord{\left/ {\vphantom {{D_{{\text{D}}_2 {\text{O}}} } {D_{{\text{H}}_2 {\text{O}}} }}} \right. \kern-\nulldelimiterspace} {D_{{\text{H}}_2 {\text{O}}} }}\) of 1.23, was determined from both FCS and from the solvent auto-diffusion coefficients obtained by NMR.
Michael T. Bowser - One of the best experts on this subject based on the ideXlab platform.
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reduced surface adsorption in 3d printed acrylonitrile butadiene styrene micro free flow electrophoresis devices
Electrophoresis, 2020Co-Authors: Sarah K. Anciaux, Michael T. BowserAbstract:We have 3D printed and fabricated micro free-flow electrophoresis (µFFE) devices in acrylonitrile butadiene styrene (ABS) that exhibit minimal surface adsorption without requiring additional surface coatings or specialized buffer additives. 2D, nano LC-micro free flow electrophoresis (2D nLC × µFFE) separations were used to assess both spatial and temporal broadening as peaks eluted through the separation channel. Minimal broadening due to wall adsorption was observed in either the spatial or temporal dimensions during separations of Rhodamine 110, Rhodamine 123, and fluorescein. Surface adsorption was observed in separations of Chromeo P503 labeled myoglobin and cytochrome c but was significantly reduced compared to previously reported glass devices. Peak widths of 20 min. A 2D nLC × µFFE separation of a Chromeo P503 labeled tryptic digest of BSA was performed to demonstrate the high peak capacity possible due to the low surface adsorption in the 3D printed ABS devices, even in the absence of surface coatings or buffer additives.
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3D Printed Micro Free-Flow Electrophoresis Device
2016Co-Authors: Sarah K. Anciaux, Matthew Geiger, Michael T. BowserAbstract:The cost, time, and restrictions on creative flexibility associated with current fabrication methods present significant challenges in the development and application of microfluidic devices. Additive manufacturing, also referred to as three-dimensional (3D) printing, provides many advantages over existing methods. With 3D printing, devices can be made in a cost-effective manner with the ability to rapidly prototype new designs. We have fabricated a micro free-flow electrophoresis (μFFE) device using a low-cost, consumer-grade 3D printer. Test prints were performed to determine the minimum feature sizes that could be reproducibly produced using 3D printing fabrication. Microfluidic ridges could be fabricated with dimensions as small as 20 μm high × 640 μm wide. Minimum valley dimensions were 30 μm wide × 130 μm wide. An acetone vapor bath was used to smooth acrylonitrile–butadiene–styrene (ABS) surfaces and facilitate bonding of fully enclosed channels. The surfaces of the 3D-printed features were profiled and compared to a similar device fabricated in a glass substrate. Stable stream profiles were obtained in a 3D-printed μFFE device. Separations of fluorescent dyes in the 3D-printed device and its glass counterpart were comparable. A μFFE separation of myoglobin and cytochrome c was also demonstrated on a 3D-printed device. Limits of detection for Rhodamine 110 were determined to be 2 and 0.3 nM for the 3D-printed and glass devices, respectively
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effect of surface adsorption on temporal and spatial broadening in micro free flow electrophoresis
Analytical Chemistry, 2015Co-Authors: Matthew Geiger, Rachel K Harstad, Michael T. BowserAbstract:Analyte adsorption onto surfaces presents a challenge for many separations, often becoming a significant source of peak broadening and asymmetry. We have shown that surface adsorption has no effect on peak position or spatial broadening in micro free flow electrophoresis (μFFE) separations. Surface adsorption does affect the time it takes an analyte to travel through the μFFE separation channel and therefore contributes to temporal broadening. These results were confirmed using μFFE separations of fluorescein, Rhodamine 110, and Rhodamine 123 in a low ionic strength buffer to promote surface adsorption. Peak widths and asymmetries were measured in both the temporal and spatial dimensions. Under these conditions Rhodamine 123 exhibited significant interactions with the separation channel surface, causing increased peak broadening and asymmetry in the temporal dimension. Broadening or asymmetry in the spatial dimension was not significantly different than that of fluorescein, which did not interact with the capillary surface. The effect of strong surface interactions was assessed using μFFE separations of Chromeo P503 labeled myoglobin and cytochrome c. Myoglobin and cytochrome c were well resolved and gave rise to symmetrical peaks in the spatial dimension even under conditions where permanent adsorption onto the separation channel surface occurred.
Sugoshr Prabhu - One of the best experts on this subject based on the ideXlab platform.
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can critical packing parameter depict probe rotation in block copolymer reverse micelles
Journal of Physical Chemistry B, 2013Co-Authors: Sugoshr Prabhu, G B DuttAbstract:Rotational diffusion of two ionic probes, cationic Rhodamine 110 (R110) and anionic fluorescein (FL), has been examined in reverse micelles formed with the triblock copolymer (EO)13–(PO)30–(EO)13 (L64), where EO and PO represent ethylene oxide and propylene oxide units, respectively, with small amounts of water in p-xylene. This study has essentially been undertaken to explore the influence of mole ratio of water to copolymer (W) as well as copolymer concentration on probe rotation. On the basis of fluorescence lifetimes and reorientation times, it has been established that both R110 and FL are located in the interfacial region of L64/water/p-xylene reverse micellar system. The average reorientation time decreases by 10–35% with an increase in W for both the probes at a given copolymer concentration. However, for a particular W, the average reorientation time increases by 10–30% as the concentration of the copolymer is enhanced. From the micellar structural parameters available in the literature, critical...
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can critical packing parameter depict probe rotation in block copolymer reverse micelles
Journal of Physical Chemistry B, 2013Co-Authors: Sugoshr Prabhu, G B DuttAbstract:Rotational diffusion of two ionic probes, cationic Rhodamine 110 (R110) and anionic fluorescein (FL), has been examined in reverse micelles formed with the triblock copolymer (EO)13–(PO)30–(EO)13 (L64), where EO and PO represent ethylene oxide and propylene oxide units, respectively, with small amounts of water in p-xylene. This study has essentially been undertaken to explore the influence of mole ratio of water to copolymer (W) as well as copolymer concentration on probe rotation. On the basis of fluorescence lifetimes and reorientation times, it has been established that both R110 and FL are located in the interfacial region of L64/water/p-xylene reverse micellar system. The average reorientation time decreases by 10–35% with an increase in W for both the probes at a given copolymer concentration. However, for a particular W, the average reorientation time increases by 10–30% as the concentration of the copolymer is enhanced. From the micellar structural parameters available in the literature, critical...
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can critical packing parameter depict probe rotation in block copolymer reverse micelles b
The Journal of Physical Chemistry, 2013Co-Authors: Sugoshr Prabhu, G B DuttAbstract:Rotational diffusion of two ionic probes, cationic Rhodamine 110 (R110) and anionic fluorescein (FL), has been examined in reverse micelles formed with the triblock copolymer (EO)₁₃–(PO)₃₀–(EO)₁₃ (L64), where EO and PO represent ethylene oxide and propylene oxide units, respectively, with small amounts of water in p-xylene. This study has essentially been undertaken to explore the influence of mole ratio of water to copolymer (W) as well as copolymer concentration on probe rotation. On the basis of fluorescence lifetimes and reorientation times, it has been established that both R110 and FL are located in the interfacial region of L64/water/p-xylene reverse micellar system. The average reorientation time decreases by 10–35% with an increase in W for both the probes at a given copolymer concentration. However, for a particular W, the average reorientation time increases by 10–30% as the concentration of the copolymer is enhanced. From the micellar structural parameters available in the literature, critical packing parameters have been calculated for the L64/water/p-xylene reverse micellar system, and it has been noticed that the average reorientation times of both the probes scale linearly with the critical packing parameter. In essence, the results of this study indicate that the probe mobility in the interfacial region of block copolymer reverse micelles is governed by the micellar packing.