Simple interface for gradient elution CEC and coupled HPLC-CEC

Robson, Mark M.; Bartle, Keith D.; Myers, Peter

doi:10.1007/bf02497309

Cited by 11 publications

(5 citation statements)

References 13 publications

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“…Because Ž most of the systems for gradient generation either . electrically or pressure generated use some kind of mixer at the head of the analytical column, part of the final mobile phase composition remains in the w x mixer after each run 8,9,24 . Additional time and solvent are required to rinse these mixers before the next run to avoid contamination.…”

Section: Resultsmentioning

confidence: 99%

Simple gradient system For capillary electrochromatography

Medina

Alonso

Barceló

et al. 2001

J Microcolumn Separations

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Abstract:A new gradient system for CEC was designed and adapted to a home-built CEC system. Chromatographic separations are initiated with a predetermined mobile phase composition and, after a desired time period, a syringe pump delivers pure organic solvent at a preset flow rate into a 2 mL vial used as the inlet buffer reservoir. Mixing is achieved by the use of a microstir bar in the buffer reservoir, which in turn is driven by an air-actuated stir plate. In this way, a convex-shaped gradient is generated, and the mobile phase is introduced into the separation column by electro-osmotic flow. Use of this system significantly reduced analysis time while still retaining acceptable reproducibility. Nonaqueous CEC was Ž . used for isocratic and gradient separation -3.5% RSD in retention times . Demonstrated applications include the analysis of triglycerides in different vegetable oil samples. This system is expected to be well suited for generating other types of gradients, such as pH and ionic strength gradients, in electroseparation techniques.

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Section: Resultsmentioning

confidence: 99%

Simple gradient system For capillary electrochromatography

Medina

Alonso

Barceló

et al. 2001

J Microcolumn Separations

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“…Robinson et al provided a simple interface for the HPLC-CE connection, which comprised of two 1/16'' Valco "Tees" [12]. Veraart et al [13] connected LC with the CE instrument via a home-made interface.…”

Section: General Aspectsmentioning

confidence: 99%

Stroboscopic sampling in comprehensive high‐performance liquid chromatography‐capillary electrophoresis via a pneumatic sampler

et al. 2004

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A new approach is presented to solve the problem of a long separation time in the second dimension of comprehensive two-dimensional chromatography. The need for a rapid separation in the second column is overcome by repeating analysis of a sample many times. In each of these individual analysis cases the sample is injected into the first dimension column and after a delay a low amount of the effluent at the end of the first column is sampled to the second-dimensional column. The time interval between the samplings from the first column to the second column is constantly increased. Thus, the system enables a comprehensive analysis of the effluent emerging from the first into the second column. This approach, which we call stroboscopic sampling, is tested for coupling high-performance liquid chromatography (HPLC) to capillary electrophoresis (CE) by an interface which operates on the principle of transporting the effluent from the HPLC column to the capillary inlet by small pressure pulses (0.5 MPa). The performance of the interface for accomplishing the comprehensive HPLC-CE analysis was demonstrated for an on-line connection of a short ion-exchange column and an ion-exclusion column to the CE capillary.

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“…Jorgenson's group has presented several different LC-CE connections, e.g., the flow-gating interface [3] and the optically gated interface [4]. Robson et al [5] have described an interface for LC-capillary electrochromatography (CEC), which also could be used for coupling LC-CE. LC-CE has also been coupled in order to increase sensitivity in the CE separation of plasma samples by using the heart-cutting technique [6].…”

Section: Introductionmentioning

confidence: 99%

On‐column polymer‐imbedded graphite inlet electrode for capillary electrophoresis coupled on‐line with flow injection analysis in a poly(dimethylsiloxane) interface

Samskog¹,

Bergström²,

Jönsson

et al. 2003

Electrophoresis

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A method for coupling an electrophoretic driven separation to a liquid flow, using conventional fused-silica capillaries and a soft polymeric interface is presented. A novel design of the electrode providing high voltage to the electrophoretic separation was also developed. The electrode consisted of a conductive polyimide/graphite imbedded coating immobilized onto the capillary electrophoresis (CE) column inlet. This integrated electrode gave the same separation performance as a commonly used platinum electrode. The on-column electrode also showed good electrochemical stability in chronoamperometric experiments. In addition, with this electrode design, the electrode position relative to the inlet end of the CE column will always be constant and well defined. The on-line flow injection analysis (FIA)-CE system was used with electrospray ionization (ESI)-time of flight (TOF)-mass spectrometry detection. The preparation of the PDMS (poly(dimethylsiloxane)) interface for FIA-CE is described in detail and used for initial tests of the on-column polymer-imbedded graphite inlet electrode. In this interface, a pressure-driven liquid flow, a make up CE electrolyte and a CE column inlet meet in a two-level cross (95 microm ID) in the PDMS structure, enabling independent flow characterization.

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Simple interface for gradient elution CEC and coupled HPLC-CEC

Cited by 11 publications

References 13 publications

Simple gradient system For capillary electrochromatography

Simple gradient system For capillary electrochromatography

Stroboscopic sampling in comprehensive high‐performance liquid chromatography‐capillary electrophoresis via a pneumatic sampler

On‐column polymer‐imbedded graphite inlet electrode for capillary electrophoresis coupled on‐line with flow injection analysis in a poly(dimethylsiloxane) interface

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