Surfactants as a Preferred Option to Improve Separation and Electrochemical Detection in Capillary Electrophoresis

Mora, María F.; Felhofer, Jessica L.; Ayón, Arturo A.; Garcı́a, Carlos D.

doi:10.1080/00032710701792927

Cited by 12 publications

(9 citation statements)

References 150 publications

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“…[6][7][8][9][10][11] The separation is based on the different residence times of the analytes if subjected to an electrical field. 12 Here, the control of the electroosmotic flow (EOF) is important to obtain an accurate analysis, especially in polymeric substrates. [13][14] Furthermore, it is desirable to tune the surface chemistry of the channel substrate to suppress any analyte-wall interactions in order to improve resolution and reproducibility.…”

Section: Introductionmentioning

confidence: 99%

“…6,8,15 Due to availability, low cost, easy concentration control and the simple removal step, surfactants may be considered as the best choice for dynamic coatings in capillary zone and microchip electrophoresis. 12,16 Surfactants also play a significant role in other important applications such as droplet microfluidics, [17][18] emulsion polymerization, [19][20][21] and stabilization of colloidal systems. 3,[22][23][24][25][26] The term surfactant refers to amphiphilic macromolecules, possessing a hydrophobic tail and a hydrophilic head.…”

Section: Introductionmentioning

confidence: 99%

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Zeta Potential of Poly(methyl methacrylate) (PMMA) in Contact with Aqueous Electrolyte–Surfactant Solutions

et al. 2017

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The addition of surfactants can considerably impact the electrical characteristics of an interface, and the zeta potential measurement is the standard method for its characterization. In this article, a comprehensive study of the zeta potential of poly(methyl methacrylate) (PMMA) in contact with aqueous solutions containing an anionic, a cationic, or a zwitterionic surfactant at different pH and ionic strength values is conducted. Electrophoretic mobilities are inferred from electrophoretic light scattering measurements of the particulate PMMA. These values can be converted into zeta potentials using permittivity and viscosity measurements of the continuous phase. Different behaviors are observed for each surfactant type, which can be explained with the various adsorption mechanisms on PMMA. For the anionic surfactant, the absolute zeta potential value below the critical micelle concentration (CMC) increases with the concentration, while it becomes rather constant around the CMC. At concentrations above the CMC, the absolute zeta potential increases again. We propose that hydrophobic-based adsorption and, at higher concentrations, the competing micellization process drive this behavior. The addition of cationic surfactant results in an isoelectric point below the CMC where the negative surface charge is neutralized by a layer of adsorbed cationic surfactant. At concentrations near the CMC, the positive zeta potential is rather constant. In this case, we propose that electrostatic interactions combined with hydrophobic adsorption are responsible for the observed behavior. The zeta potential in the presence of zwitterionic surfactant is influenced by the adsorption, because of hydrophobic interactions between the surfactant tail and the PMMA surface. However, there is less influence, compared to the ionic surfactants. For all three surfactant types, the zeta potential changes to more-negative or less-positive values for alkaline pH values, because of hydroxide adsorption. An increase of the ionic strength decreases the absolute value of the zeta potential, because of the shielding effects.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Zeta Potential of Poly(methyl methacrylate) (PMMA) in Contact with Aqueous Electrolyte–Surfactant Solutions

et al. 2017

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“…In recent years, this method of amperometric measurement was employed, e.g. in CE of surfactants [180], carbohydrates [181], and also amines [182]. Submicromolar detection limits reported in the last case are lower than the ones obtained for UV detection, and comparable or lower than laser-induced fluorescence detection results reported in the literature.…”

Section: Amperometric Detection In Capillary Electrophoresismentioning

confidence: 43%

Recent developments in electrochemical flow detections—A review

Trojanowicz

2009

Analytica Chimica Acta

129

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“…5C) was observed. This drift has been attributed to unstable μ EOF values, a common problem associated with PDMS chips 2, 15, 45, 57, 58. These experiments demonstrate the possibility of performing remote analysis of air samples using the proposed device.…”

Section: Resultsmentioning

confidence: 99%

Lab‐on‐a‐robot: Integrated microchip CE, power supply, electrochemical detector, wireless unit, and mobile platform

et al. 2008

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In this paper, the fabrication of a wireless mobile unit containing an electrochemical detection module and a 3-channel high-voltage power supply (HVPS) designed for microchip CE is described. The presented device consists of wireless global positioning system controlled robotics, an electrochemical detector utilizing signal conditioning analog circuitry and a digital feedback range controller, a HVPS, an air pump, and a CE microchip. A graphical user interface (LabVIEW) was also designed to communicate wirelessly with the device, from a distant personal computer communication port. The entire device is integrated and controlled by digital hardware implemented on a field programmable gate array development board. This lab-on-a-robot is able to navigate to a global position location, acquire an air sample, perform the analysis (injection, separation, and detection), and send the data (electropherogram) to a remote station without exposing the analyst to the testing environment.

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Surfactants as a Preferred Option to Improve Separation and Electrochemical Detection in Capillary Electrophoresis

Cited by 12 publications

References 150 publications

Zeta Potential of Poly(methyl methacrylate) (PMMA) in Contact with Aqueous Electrolyte–Surfactant Solutions

Zeta Potential of Poly(methyl methacrylate) (PMMA) in Contact with Aqueous Electrolyte–Surfactant Solutions

Recent developments in electrochemical flow detections—A review

Lab‐on‐a‐robot: Integrated microchip CE, power supply, electrochemical detector, wireless unit, and mobile platform

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