Capillary zone electrophoresis of complex ionic mixtures with on-line isotachophoretic sample pretreatment

Kaniansky, Dušan; Marák, Jozef; Madajová, V.; Šimuničová, E.

doi:10.1016/0021-9673(93)83422-o

Cited by 77 publications

(26 citation statements)

References 33 publications

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“…Capillary ITP on-line combined with CZE in the coupledcolumns (ITP-CZE), as introduced previously [10], provides very significant CE tools as applicable to biological samples [11,12]. Analytically, it is very convenient that the ITP-CZE combination integrates one electrophoresis run [12][13][14][15][16] and, in fact, includes: (i) the ITP and CZE separations, (ii) ITP concentrations of the analytes, (iii) ITP sample clean-up, and (iv) ITP enhancing a high sample load capacity (for example, by a factor of 10 3 or more in comparison to a current singlecolumn).…”

Section: Introductionmentioning

confidence: 99%

Enantioselective analysis of pheniramine in urine by charged CD‐mediated CZE provided with a fiber‐based DAD and an on‐line sample pretreatment by capillary ITP

et al. 2007

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Application potentialities of CZE on-line coupled with capillary ITP and DAD to the identification and determination of trace concentration levels (microg/L) of pheniramine (PHM) enantiomers and their metabolites present in complex ionic matrices of biological origin (urine) are shown. An enhanced (enantio)selectivity of the CZE separation system obtained by the addition of carboxyethyl-beta-CD (CE-beta-CD) to the carrier electrolyte provided CZE conditions for a reliable identification of similar/identical DAD spectra of structurally related compounds (PHM enantiomers and their metabolites) in clinical urine samples differing in qualitative and quantitative composition of sample matrix constituents. A high sample loadability (a 30 microL sample injection volume), partial sample clean-up (removing macroconstituents from the sample), and preconcentration of the analytes in ITP stage resulted in the decrease of concentration LOD for PHM enantiomers in urine to 5.2 and 6.8 microg/L (2.2 x 10(-8) and 2.8 x 10(-8) mol/L), without using any sample pretreatment technique. The background correction and smoothing procedure applied to the raw DAD spectra provided analytically relevant DAD spectra of PHM enantiomers and their metabolites also when they were present in urine sample (30 microL injection volumes of ten-times diluted urine sample) at a 9 x 10(-) (8) mol/L concentration. DAD spectra of PHM enantiomers present in urine samples matched their reference spectra with reasonable certainties. DAD spectra of PHM metabolites were compared with the reference spectra of PHM enantiomers and a good match was found which indicates the similarities in the structures of enantiomers and their metabolites detected in the urine samples. This fact allows performing the quantitative analyses of PHM metabolites in the urine samples by applying the calibration parameters of PHM enantiomers also for PHM metabolites and the results show the possibilities of using the ITP-CZE-DAD combination for the direct analysis of PHM enantiomers and/or their metabolites in urine without any sample pretreatment. ITP-CZE-DAD method with oppositely charged selector is suggested to use in clinical research as it provides favorable performance parameters including sensitivity, linearity, precision, recovery, and robustness with minimal demands on sample preparation.

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Section: Introductionmentioning

confidence: 99%

Enantioselective analysis of pheniramine in urine by charged CD‐mediated CZE provided with a fiber‐based DAD and an on‐line sample pretreatment by capillary ITP

et al. 2007

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“…The concentration of the analyte in its zone is given by Kohlrausch regulation function and does not depend on the concentration of the analyte in the injected sample. Mainly due to this fact ITP is usually used as an on-line sample pretreatment technique before CZE or other (usually electrophoretic) separation technique [20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Some possibilities of an analysis of complex samples by a mass spectrometry with a sample pretreatment by an offline coupled preparative capillary isotachophoresis

et al. 2011

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This work deals with an analysis of biologically important compounds in complex matrices using preparative isotachophoresis (pITP) in column coupling configuration as a sample pretreatment technique followed by a direct infusion mass spectrometry with nano-electrospray ionization (DI-nESI-MS). Busereline was chosen as a model analyte, and urine was chosen as an example of complex matrix. In pITP experiments, sodium cation (10 mmol/L concentration) was used as a leading ion and β-alanine as terminating ion (20 mmol/L concentration). The fractions, obtained by pITP pre-separation with the assistance of the mixture of discrete spacers, were finally analyzed by DI-nESI-MS. It was shown that pITP performed before DI-nESI-MS analysis can significantly simplify complex matrix, and, due to its concentration power, pITP can consequently decrease the concentration limit of detection. The concentration of buserelin in the urine samples analyzed by pITP-DI-nESI-MS was 10 μg/L (reflecting at a 8.10⁻⁹ mol/L concentration) in our work but from the ion intensities obtained in MS as well as MS/MS analyses, it is clear that this concentration level could be several orders of magnitude lower for reliable detection and identification of buserelin in urine analyzed using pITP with DI-nESI-MS detection.

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“…The combinations of techniques are excellent for the purpose of preconcentration, preseparation, and sample cleanup prior to sensitive CZE detection step. They are less convenient for analyses of ampholytes, because bulk of ionic substances is preconcentrated and the sample must be cleaned up [2][3][4]. CIEF, as a quasi-steady-state technique, was designed for the separations of ampholytes [5].…”

Section: Introductionmentioning

confidence: 99%

Analysis of amino acids by combination of carrier ampholyte‐free IEF with ITP

2007

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The use of carrier ampholyte-free IEF (CAF-IEF) with ITP mobilization and conductivity detection in ITP mode for preconcentration and analysis of amino acids is demonstrated. The analytical procedure consists of three subsequent steps. In the first step, amino acids are continuously dosed from an infinite volume reservoir by electromigration to the column, where a sharp, stationary neutralization reaction boundary (NRB) is created in between acidic and basic primary electrolyte. Here, amino acids are selectively focused (trapped), if their pI falls to the pH difference on both sides of the NRB (pH gap). Amino acids create sharp rectangular zones, arranged according to their pI values. In the second step, focused zones are mobilized. After accumulation of the detectable amount of amino acids, dosing electrolyte in the infinite volume reservoir is changed for the mobilizing electrolyte. The migration mode is changed from CAF-IEF to ITP and substances start to migrate toward the analytical capillary. In the third step, analytes are transferred into the analytical column equipped with a conductivity detector and are detected in the new leading electrolyte in an ITP migration mode. The presented CAF-IEF-ITP-ITP with time-dependent accumulation of the large-volume sample enables to achieve in a reasonable time a 100 times lower c-LOD (here in orders of nmol/L), than can be reached by conventional hyphenated ITP-ITP.

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Capillary zone electrophoresis of complex ionic mixtures with on-line isotachophoretic sample pretreatment

Cited by 77 publications

References 33 publications

Enantioselective analysis of pheniramine in urine by charged CD‐mediated CZE provided with a fiber‐based DAD and an on‐line sample pretreatment by capillary ITP

Enantioselective analysis of pheniramine in urine by charged CD‐mediated CZE provided with a fiber‐based DAD and an on‐line sample pretreatment by capillary ITP

Some possibilities of an analysis of complex samples by a mass spectrometry with a sample pretreatment by an offline coupled preparative capillary isotachophoresis

Analysis of amino acids by combination of carrier ampholyte‐free IEF with ITP

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