Alternating Voltage Capillary Electrochromatography

Nakagawa, Hiroyuki; Satô, Masahiko; Kitagawa, Shinya; Tsuda, Toshitaka

doi:10.1021/ac034064e

Cited by 10 publications

(7 citation statements)

References 13 publications

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“…Tsuda et al have also shown that the retention factors of neutral [167,168] and charged [169,170] analytes can be affected and controlled by application of an electric field. Lately these authors have also shown similar results with the use of alternating voltage [171].…”

Section: Controlling the Retention With Electricitysupporting

confidence: 60%

Controlling the retention in capillary LC with solvents, temperature, and electric fields

Jandera

Blomberg

Lundanes³

2004

J of Separation Science

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Once a suitable stationary phase and column dimensions have been selected, the retention in liquid chromatography (LC) is traditionally adjusted by controlling the mobile phase composition. Solvent gradients enable achievement of good separation selectivity while decreasing the separation time as compared to isocratic elution. Capillary columns allow use of other programming parameters, i.e. temperature and applied electric fields, in addition to solvent gradient elution. This paper presents a review of programmed separation techniques in miniaturized LC, including retention modeling and method transfer from the conventional to micro- and capillary scales. The impact of miniaturized instrumentation on retention and the limitations of capillary LC are discussed. Special attention is focused on the gradient dwell volume effects, which are more important in micro-LC techniques than in conventional analytical LC and may cause significant increase in the time of analysis, unless special instrumentation and (or) pre-column flow-splitting is used. The influence of temperature upon retention is also discussed, and applications where the temperature has been actively used for retention control in capillary LC are included together with the instrumentation utilized. Finally the possibilities of additional selectivity control by applying an electric field over a packed capillary LC column are discussed.

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Section: Controlling the Retention With Electricitysupporting

confidence: 60%

Controlling the retention in capillary LC with solvents, temperature, and electric fields

Jandera

Blomberg

Lundanes³

2004

J of Separation Science

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show abstract

“…Tsuda et al have also shown that retention factors can be affected and controlled by application of an electric field on neutral [36,37] and charged [38,39] analytes. Lately, they have also shown similar results with the use of alternating voltage [40].…”

Section: Introductionsupporting

confidence: 52%

Changes in mobile phase ion distribution when combining pressurized flow and electric field

et al. 2004

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The distribution of ions in a capillary with both pressurized flow and an electric field has been studied. We have earlier reported that the overall concentration of ions increase in a capillary with high electric field and a pressurized flow. Now we describe how the ions are distributed in the capillary both along the capillary length and in the radial direction as a result of the parabolic flow profile. We have combined current measurements with finite element techniques in order to get better understanding of the system. We have found that the concentration of the ions that because of the electric mobility moves towards the flow primarily increases at the beginning of the electric field and close to the capillary wall. In view of the results we have proposed an alterative explanation of earlier published results concerning voltage-induced variation in capacity factors.

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“…The CEC method possesses high separation efficiency due to the very flat flow profile, which is generated by the electroosmotically driven mobile phase. Depending on both assisted pressure and electric field, the pCEC separation efficiency is between that of CEC and HPLC [40][41][42]. When the electroosmotic flow is predominantly responsible for driving the flow of mobile phase, high separation efficiency could be obtained.…”

Section: Effect Of Assisted Pressure and Separation Voltage On Separamentioning

confidence: 99%

Pressure‐assisted capillary electrochromatography with electrospray ionization‐mass spectrometry based on silica‐based monolithic column for rapid analysis of narcotics

Zhang

Feng

et al. 2008

Electrophoresis

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A pressure-assisted CEC (pCEC) with ESI-MS based on silica-based monolithic column was developed for rapid analysis of narcotics. Combining the extremely high permeability and separation efficiency of silica-based monolithic column with the high selectivity and sensitivity of pCEC-ESI-MS, the developed system exhibited its prominent advantages in separation and detection. A systematic investigation of the pCEC separation and ESI-MS detection parameters was performed. Experiment results showed that the optimized separation efficiency could be obtained at 8 bar assisted pressure with 25 kV separation voltage, using the solution containing 65% ACN v/v and 20 mmol/L ammonium acetate with pH 6.0 as running buffer. 3 microL/min of sheath liquid was considered as the optimized flow rate since it could provide the maximum signal intensity. Under the optimum conditions, the tested five narcotics could be completely separated within 10 min with the detection limit in the range of 2.0-80 nmol/L. The proposed method has been successfully used for detection of narcotics in real urine samples.

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Alternating Voltage Capillary Electrochromatography

Cited by 10 publications

References 13 publications

Controlling the retention in capillary LC with solvents, temperature, and electric fields

Controlling the retention in capillary LC with solvents, temperature, and electric fields

Changes in mobile phase ion distribution when combining pressurized flow and electric field

Pressure‐assisted capillary electrochromatography with electrospray ionization‐mass spectrometry based on silica‐based monolithic column for rapid analysis of narcotics

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