Gradient Elution System for Packed Capillary Column Liquid Chromatography

Andreolini, Franca; Trisciani, Adriano

doi:10.1093/chromsci/28.2.54

Cited by 6 publications

(3 citation statements)

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“…Received May 8, 1997 Accepted June 6, 1997 Fig. 2 Step-gradient CEC separation of six commonly used diuretic compounds (1)(2)(3)(4)(5)(6). CEC conditions as in Fig.…”

Section: Paper 7/03175kmentioning

confidence: 99%

“…In order to realise the full potential of CEC, it is necessary to develop the capacity of gradient elution for the separation of complex mixtures of widely differing lipophilicities as in HPLC. 1,2 Several publications have reported encouraging results using gradient CEC with 'home-built' systems. 3,4 This prompted us to investigate the feasibility of employing step-gradient CEC on commercially available CE equipment in order to widen the scope of current CEC applications.…”

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confidence: 99%

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Step-gradient Capillary Electrochromatography

Euerby¹,

Gilligan²,

Johnson³

et al. 1997

Analyst

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The analytical benefits of using a step-gradient in capillary electrochromatography (CEC) are demonstrated. The application of step-gradient CEC to the analysis of six diuretics of widely differing lipophilicities was evaluated and shown to result in a marked reduction in the analysis time and an improvement in the peak shape for later-eluting lipophilic components. When the step-gradient approach was performed in an automated mode, the retention time RSD for repeated injections was below 1%.

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“…Received May 8, 1997 Accepted June 6, 1997 Fig. 2 Step-gradient CEC separation of six commonly used diuretic compounds (1)(2)(3)(4)(5)(6). CEC conditions as in Fig.…”

Section: Paper 7/03175kmentioning

confidence: 99%

mentioning

confidence: 99%

Step-gradient Capillary Electrochromatography

Euerby¹,

Gilligan²,

Johnson³

et al. 1997

Analyst

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“…To realize the full potential of CEC, it is necessary to develop the capability of gradient elution, as in HPLC and micro-HPLC, , for successfully separating a wide variety of complex samples. So far, there appears to be no report on solvent gradient elution in CEC using direct, electroosmotically driven flow in packed capillary columns in an automated manner.…”

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confidence: 99%

Gradient Elution in Capillary Electrochromatography

Yan¹,

Dadoo²,

Zare³

et al. 1996

Anal. Chem.

143

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In analogy to pressure-driven gradient techniques in high-performance liquid chromatography, a system has been developed for delivering electroosmotically driven solvent gradients for capillary electrochromatography (CEC). Dynamic gradients with submicroliter per minute flow rates are generated by merging two electroosmotic flows that are regulated by computer-controlled voltages. These flows are delivered by two fused-silica capillary arms attached to a T-connector, where they mix and then flow into a capillary column that has been electrokinetically packed with 3-μm reversed-phase particles. The inlet of one capillary arm is placed in a solution reservoir containing one mobile phase, and the inlet of the other is placed in a second reservoir containing a second mobile phase. Two independent computer-controlled, programmable, high-voltage power supplies (0−50 kV)one providing an increasing ramp and the other providing a decreasing rampare used to apply variable high-voltage potentials to the mobile phase reservoirs to regulate the electroosmotic flow in each arm. The ratio of the electroosmotic flow rates between the two arms is changed with time according to the computer-controlled voltages to deliver the required gradient profile to the separation column. Experiments were performed to confirm the composition of the mobile phase during a gradient run and to determine the change of the composition in response to the programmed voltage profile. To demonstrate the performance of electroosmotically driven gradient elution in CEC, a mixture of 16 polycyclic aromatic hydrocarbons was separated in less than 90 min. This gradient technique is expected to be well-suited for generating not only solvent gradients in CEC but also other types of gradients, such as pH and ionic strength gradients, in capillary electrokinetic separations and analyses.

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