Eigenmobilities in background electrolytes for CZE. V. Intensity (amplitudes) of system peaks

Hruška, Vlastimil; Štědrý, Milan; Včeláková, Kateřina; Lokajová, Jana; Tesařová, Eva; Jaroš, Michal; Gaš, Bohuslav

doi:10.1002/elps.200600277

Cited by 24 publications

(32 citation statements)

References 16 publications

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“…(Adapted from [11], with permission.) most of them the other eigenmobility is very small and forms a stationary system zone which can serve in practice as the EOF marker.…”

Section: Non-conservation Systemsmentioning

confidence: 97%

Prediction and understanding system peaks in capillary zone electrophoresis

Gaš¹,

Hruška²,

Dittmann³

et al. 2007

J of Separation Science

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Introduction of a sample into the separation column (microchip channel) in capillary zone electrophoresis (microchip electrophoresis) will cause a disturbance in the originally uniform composition of the background electrolyte. The disturbance, a system zone, can move in some electrolyte systems along the separation channel and, on reaching the position of the detector, cause a system peak. As shown by the linear theory of electromigration based on linearized continuity equations formulated in matrix form, the mobility of the system zone--the system eigenmobility--can be obtained as the eigenvalue of the matrix. Progress in the theory of electromigration allows us to predict the existence and mobilities of the system zones, even in very complex electrolyte systems consisting of several multivalent weak electrolytes, or in micellar systems (systems with SDS micelles) used for protein sizing in microchips. The theory is implemented in PeakMaster software, which is available as freeware (www.natur.cuni.cz/gas). The linearized theory also predicts background electrolytes having no stationary injection zone (water zone, water gap, water dip, EO zone) or unstable electrolyte systems exhibiting oscillations and creating periodic structures. The oscillating systems have complex system eigenmobilities (eigenvalues of the matrix are complex). This paper reviews the theoretical background of the system peaks (system eigenpeaks) and gives practical hints for their prediction and for preparing background electrolytes not perturbed by the occurrence of system peaks and by excessive peak broadening.

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“…(Adapted from [11], with permission.) most of them the other eigenmobility is very small and forms a stationary system zone which can serve in practice as the EOF marker.…”

Section: Non-conservation Systemsmentioning

confidence: 97%

Prediction and understanding system peaks in capillary zone electrophoresis

Gaš¹,

Hruška²,

Dittmann³

et al. 2007

J of Separation Science

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“…System peaks are peaks that are recorded by the detector but they are not associated with any separated analyte. System peaks are in fact disturbing phenomena accompanying separation in CZE [18]. They are moving disturbances in the originally uniform concentration of the BGE, which were originally caused by the injection of the sample into the separation column.…”

Section: Introductionmentioning

confidence: 98%

System peaks in micellar electrophoresis: I. Utilization of system peaks for determination of critical micelle concentration

et al. 2008

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A new way to determine the critical micelle concentration (CMC) based on the mobilities of system peaks is presented. A general approach for the CMC determination is based on the change of the slope or on finding the inflection point in the plot of a physical property of solution as a function of surfactant concentration. The determination of CMC by system peaks in CE utilizes a "jump" instead of a continuous change in the measured quantity. This phenomenon was predicted by the program PeakMaster, which was modified for simulation of micellar systems. The simulation of the steep change in mobilities of the anionic system peaks showing the CMC value was verified experimentally in a set of measurements, where the concentration of the surfactant was varied while the ionic strength was kept constant. The experimental work fully proved our model. A comparative electric current measurement was carried out. The proposed method seems to offer easier CMC determination as compared to the standard methods.

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“…Recent published works do now allow predicting system peaks in a given BGE [14,25], and such approaches seem critical to obtain a robust method when using an indirect detection scheme [1,14,26,27]. As pointed out by Beckers and Bocek [28], multivalent weak electrolytes should be avoided when possible.…”

Section: Discussionmentioning

confidence: 98%

“…However, for more complex BGE, such as the ones containing multivalent co-ions and/or weak analytes, no analytical solutions have been proposed so far and numerical simulations are a valuable tool [11,12] to maximise the sensitivity of key analytes. For example, it has been shown that when the mobility of an analyte becomes closer to the one of a system peak, the TR value increases [13,14] until the extreme case where the mobility of an analyte equals the mobility of a system peak. In this case, a resonance phenomenon occurs and the response in indirect detection grows with time [15].…”

Section: Introductionmentioning

confidence: 97%

Robustness of the co‐ion transfer ratio in capillary electrophoresis

Erny¹,

Esteves

2009

J of Separation Science

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In CE, indirect detection mode often exhibits a lower precision than its direct counterpart. Although various explanations have already been advanced, in this work, we aimed to investigate if this is due, in part, to problems of robustness of the co-ion transfer ratio (TR), thus being inherent to this particular detection scheme. This was investigated using simulation software that allows an accurate control of various parameters and validated using acetic acid as a test compound. It was conclusively demonstrated that the TR could vary by more than 6% when the concentration of one of the ions in the BGE was changed by as few as 1%. The presence of a system peak seems to be particularly damaging as it has been shown that the TR of peaks whose mobilities differ by more than 0.5x10(-8) m(2) V(-1) s(-1) from one of the system peaks, still have a relatively low robustness.

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Eigenmobilities in background electrolytes for CZE. V. Intensity (amplitudes) of system peaks

Cited by 24 publications

References 16 publications

Prediction and understanding system peaks in capillary zone electrophoresis

Prediction and understanding system peaks in capillary zone electrophoresis

System peaks in micellar electrophoresis: I. Utilization of system peaks for determination of critical micelle concentration

Robustness of the co‐ion transfer ratio in capillary electrophoresis

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