An Oscillometric Detector for Capillary Electrophoresis

Silva, José Alberto Fracassi da; Lago, Claudimir Lúcio do

doi:10.1021/ac980185g

Cited by 500 publications

(238 citation statements)

References 19 publications

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“…However, C 4 D can be recorded along the entire length of a column non-invasively, with the recorded response directly proportional to the sum of conducting elements within the , virtual electrode area' [22][23][24][25][26][27]. The presence of non-conducting monolithic phase filled with a background solution, housed within a fused silica capillary of uniform character, will provide a conductive response proportional to the fluid volume.…”

Section: Cross-validation Of the C 4 D Methodologymentioning

confidence: 99%

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Evaluation of photografted charged sites within polymer monoliths in capillary columns using contactless conductivity detection

Connolly

O'Shea

Clark

et al. 2007

J of Separation Science

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Original PaperEvaluation of photografted charged sites within polymer monoliths in capillary columns using contactless conductivity detection Capacitively coupled contactless conductivity detection (C 4 D) is presented as a novel and versatile means of visualising discrete zones of charged functional groups grafted onto polymer based monoliths. Monoliths were first formed within 100 lm UV-transparent fused silica capillaries. Photografting methods were subsequently used to graft a charged functional monomer, 2-acrylamido-2-methyl-1-propanesulfonic acid, onto discrete regions of the monolith using a photomask. Post-modification monolith evaluation involves scanning the C 4 D detector along the length of the monolith to obtain a profile of the exact spatial location of grafted charged functionalities with millimetre accuracy. The methodology was extended to the visualisation of several zones of immobilised protein (bovine serum albumin) using photografted azlactone groups to enable covalent attachment of the protein to the monolith at precise locations along its length. In addition, the extent of non-specific binding of protein to the ungrafted regions of the monolith due to hydrophobic interactions could be monitored as an increase in background conductivity of the stationary phase. Finally, the technique was cross-validated using digital photography in combination with a UV light source by immobilising green fluorescent protein in discrete zones and comparing the results obtained using both complementary techniques.

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Section: Cross-validation Of the C 4 D Methodologymentioning

confidence: 99%

“…The principles of C 4 D have been well studied [22][23][24][25][26][27], and the electronic circuitry has been found to be simple and of low cost. The advantage of C 4 D over conventional conductivity detection for chromatography is that the cell design is extremely robust and there is a lack of physical contact with the eluent.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of photografted charged sites within polymer monoliths in capillary columns using contactless conductivity detection

Connolly

O'Shea

Clark

et al. 2007

J of Separation Science

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“…Because of its good separation efficiency and low specific conductivity value, MES/His buffers have been widely used as running electrolyte solution, especially for the applications using conductivity detection [51,53]. Furthermore, its pH-value is ideal for the complete ionization of VPA.…”

Section: Separation Voltage and Buffer Optimizationmentioning

confidence: 99%

Direct determination of valproic acid in biological fluids by capillary electrophoresis with contactless conductivity detection

Belin

Krähenbühl

Hauser

2007

Journal of Chromatography B

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Capacitively coupled contactless conductivity detection (C 4 D) is a new technique providing high sensitivity in capillary electrophoresis (CE) especially for small ions that can otherwise only be determined with indirect methods. In this work, direct determination and validation of valproic acid (VPA) in biological fluids was achieved using CE with C 4 D. VPA is of pharmacological interest because of its use in epilepsy and bipolar disorder. The running electrolyte solution used consisted of 10 mM 2-(N-morpholino)ethane sulfonic acid (MES)/dl-histidine (His) and 50 M hexadecyltrimethylammonium bromide (HTAB) at pH 6.0. Caproic acid (CA) was selected as internal standard (IS). Analyses of VPA in serum, plasma and urine samples were performed in less than 3 min. The interference of the sample matrix was reduced by deproteinization of the sample with acetonitrile (ACN). The effect of the solvent type and ratio on interference was investigated. The limits of detection (LOD) and quantitation (LOQ) of VPA in plasma samples were determined as 24 and 80 ng/ml, respectively. The method is linear between the 2 and 150 g/ml, covering well the therapeutic range of VPA (50-100 g/ml).

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“…Slightly different CCD techniques were proposed for HPCE in 1998 [304,305] and subsequently improved (for reviews see refs. [306][307][308][309][310]).…”

Section: Contact and Contactless Conductivity Detection (Cd Ccd C 4mentioning

confidence: 99%

Bioanalytical profile of the l-arginine/nitric oxide pathway and its evaluation by capillary electrophoresis

Boudko

2007

Journal of Chromatography B

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This review briefly summarizes recent progress in fundamental understanding and analytical profiling of the L-arginine/nitric oxide (NO) pathway. It focuses on key analytical references of NO actions and on the experimental acquisition of these references in vivo, with capillary electrophoresis (CE) and high-performance capillary electrophoresis (HPCE) comprising one of the most flexible and technologically promising analytical platform for comprehensive high-resolution profiling of NO-related metabolites. Second aim of this review is to express demands and bridge efforts of experimental biologists, medical professionals and chemical analysis-oriented scientists who strive to understand evolution and physiological roles of NO and to develop analytical methods for use in biology and medicine.

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An Oscillometric Detector for Capillary Electrophoresis

Cited by 500 publications

References 19 publications

Evaluation of photografted charged sites within polymer monoliths in capillary columns using contactless conductivity detection

Evaluation of photografted charged sites within polymer monoliths in capillary columns using contactless conductivity detection

Direct determination of valproic acid in biological fluids by capillary electrophoresis with contactless conductivity detection

Bioanalytical profile of the l-arginine/nitric oxide pathway and its evaluation by capillary electrophoresis

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