Detectability improvements in capillary zone electrophoresis by combining single capillary isotachophoretic preconcentration and frequency doubled argon ion laser‐induced fluorescence detection

Enlund, Anna Maria; Schmidt, Staffan; Westerlund, Douglas

doi:10.1002/elps.1150190518

Cited by 18 publications

(14 citation statements)

References 42 publications

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“…This combination has been already reported for the microfluidic devices . A single capillary approach based on ITP assisted with a counter‐pressure, followed by CZE and hyphenated with LIF has been demonstrated by Enlund et al . This method allowed quantifying a 1 ng/mL concentration of a new cholinesterase inhibitor as the analyte.…”

Section: Introductionmentioning

confidence: 87%

On‐line coupled capillary isotachophoresis‐capillary zone electrophoresis in hydrodynamically closed separation system hyphenated with laser induced fluorescence detection

et al. 2013

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An analytical method, based on a column coupling capillary ITP and CZE in a hydrodynamically closed separation mode hyphenated with the detection in the modular arrangement, was developed in this work. Analytical possibilities of this approach are demonstrated on the direct and ultrasensitive quantitative determination of quinine (QUI) in diluted real multicomponent ionic matrices (beverages, urine). The detection cell interface, with the rectangular arrangement of the optical channels inside, connected the separation capillary with the LIF detector via optical fibers in the on-column detection arrangement. ITP enabled the direct large volume (30 μL) injections of the diluted real matrices with an on-line sample pretreatment (preseparation, preconcentration) so that no external sample preparation (except for the dilution) was necessary for the separation of the analyte in the multicomponent ionic matrices. Due to the ITP sample preconcentration and intrinsic sensitivity of the LIF detection, very low concentration LOD (as low as 77 pg/mL), were reached at the same time. This was ca. two orders lower than the corresponding LOD achieved by the same 2D separation system with UV absorbance detection. Compared to the single column CE-LIF methods applied for this model analyte and matrix, this method was found to be superior in terms of concentration LOD, with acceptable selectivity and benefits of the on-line sample preparation. A food control and bioanalytical application clearly illustrates great practical possibilities and routine use of the proposed modular ITP-CZE-LIF technique.

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Section: Introductionmentioning

confidence: 87%

On‐line coupled capillary isotachophoresis‐capillary zone electrophoresis in hydrodynamically closed separation system hyphenated with laser induced fluorescence detection

et al. 2013

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“…One limitation of conventional tITP is that only a certain portion of the capillary length can be filled with the sample while the rest should be reserved for the subsequent CZE. One way to overcome this limitation is pushing back the isotachophoretically stacked zones toward the inlet by a counter pressure, thus using most of the capillary length for both stacking and separation . However, the amount of injected sample is still limited by the capillary length.…”

Section: Introductionmentioning

confidence: 99%

Highly sensitive analysis of catecholamines by counter‐flow electrokinetic supercharging in the constant voltage mode

Kwon

Chang

Jang

et al. 2013

J of Separation Science

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Electrokinetic supercharging is one of the most powerful sample-stacking methods that combines field amplified sample injection and transient ITP. In counter-flow electrokinetic supercharging, a constant counter pressure is applied during sample injection in order to counterbalance the movement of the injected sample zone. As a result, there will be a pronounced increase in the amount of sample injected and the portion of the capillary available for electrophoresis. In this report, counter-flow electrokinetic supercharging optimization factors such as the electric field application in the constant voltage and constant current modes, the magnitude of counter pressure, and the terminating electrolyte concentrations were investigated. The enrichments obtained with a 30 min injection of 10 nM catecholamines in 5 mM terminating electrolyte solution in the constant voltage mode applying a counter pressure of 1.3 psi were 41,000-fold for dopamine, 50,000-fold for norepinephrine, and 32,000-fold for epinephrine, yielding detection limits of 1.3, 1.4, and 1.2 nM, respectively, with absorbance detection at 200 nm.

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“…Therefore, several methods have been used to enhance the sensitivity of CE. In addition to instrumental methods, such as high‐sensitive detectors 1, 2 and lengthening optical path‐length at detection window 3, some pre‐concentration techniques such as sweeping, 4, 5 field‐amplified sample stacking 6, 7, transient ITP 8, 9, dynamic pH junction 10, 11, solid‐phase microextraction (SPME) 12, 13, membrane extraction 14, 15, supercritical fluid extraction 16, and so on have been coupled with CE for concentrating analytes before separation and arrival to the detector.…”

Section: Introductionmentioning

confidence: 99%

A new open tubular capillary microextraction and sweeping for the analysis of super low concentration of hydrophobic compounds

Xia

Ting-ting

Chen

et al. 2010

J of Separation Science

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A sample pre-concentration method based on the in-line coupling of in-tube solid-phase microextraction and electrophoretic sweeping was developed for the analysis of hydrophobic compounds. The sample pre-concentration and electrophoretic separation processes were simply and sequentially carried out with a (35%-phenyl)-methylpolysiloxane-coated capillary. The developed method was validated and applied to enrich and separate several pharmaceuticals including loratadine, indomethacin, ibuprofen and doxazosin. Several parameters of microextration were investigated such as temperature, pH and eluant. And the concentration of microemulsion that influences separation efficiency and microextraction efficiency were also studied. Central composite design was applied for the optimization of sampling flow rate and sampling time that interact in a very complex way with each other. The precision, sensitivity and recovery of the method were investigated. Under the optimal conditions, the maximum enrichment factors for loratadine, indomethacin, ibuprofen and doxazosin in aqueous solutions are 1355, 571, 523 and 318, respectively. In addition, the developed method was applied to determine loratadine in rabbit blood sample.

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Detectability improvements in capillary zone electrophoresis by combining single capillary isotachophoretic preconcentration and frequency doubled argon ion laser‐induced fluorescence detection

Cited by 18 publications

References 42 publications

On‐line coupled capillary isotachophoresis‐capillary zone electrophoresis in hydrodynamically closed separation system hyphenated with laser induced fluorescence detection

On‐line coupled capillary isotachophoresis‐capillary zone electrophoresis in hydrodynamically closed separation system hyphenated with laser induced fluorescence detection

Highly sensitive analysis of catecholamines by counter‐flow electrokinetic supercharging in the constant voltage mode

A new open tubular capillary microextraction and sweeping for the analysis of super low concentration of hydrophobic compounds

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