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General approach for certain quantitative calculations for Instance of the variance of reversible adsorption to the capillary wall in CE

Farkas, Viktor; Rezeli, Melinda LU ; Végvári, Ákos LU ; Kilár, Ferenc and Hjertén, Stellan (2009) In Analytical Chemistry 81(1). p.343-348
Abstract
Miniaturization of analytical separation methods offers several advantages, including short run times, high resolution, and high recovery of the sample constituents. To optimize these parameters, the reversible adsorption (to minimize loss in resolution), as well as the irreversible adsorption (to minimize loss of analytes) must be quantified. However, no useful equation is available for the calculation of the variance of reversible adsorption. Therefore, we have taken another approach to quantify the reversible interaction. The method is unique and important since no equation for calculation of this variance is required. Instead, two experiments are required, which are run under such conditions that the variance of a certain parameter has... (More)
Miniaturization of analytical separation methods offers several advantages, including short run times, high resolution, and high recovery of the sample constituents. To optimize these parameters, the reversible adsorption (to minimize loss in resolution), as well as the irreversible adsorption (to minimize loss of analytes) must be quantified. However, no useful equation is available for the calculation of the variance of reversible adsorption. Therefore, we have taken another approach to quantify the reversible interaction. The method is unique and important since no equation for calculation of this variance is required. Instead, two experiments are required, which are run under such conditions that the variance of a certain parameter has the same numerical value in the two experiments (one with and without EOF), except for the variance of reversible adsorption. The approach is universal in the sense that it can be used for many different mathematical concepts and be modified to also cover certain functions other than a sum of parameters. We have also introduced a simple expression for the irreversible adsorption, which shows that the hydrophobic interaction from only two methyl groups in the coating gives rise to as much as 40-50% loss of protein, and the width of the zones in the capillary with this coating was 8-15% larger compared to the zone width in the polyacrylamide-coated capillaries. The reproducibility in migration time, peak area, and peak width in two consecutive runs in capillaries with two methyl groups in the coating was very low, but in EOF-free polyacrylamide-coated capillaries extremely high, indicating that the reversible and irreversible adsorption of proteins to this coating is negligible. The scanning detector, frequently used in free zone electrophoresis in the 1960s-1970s, gives true separation parameters and is, therefore, much preferable to the stationary detector used in most CE experiments, because this detector gives apparent separation parameters. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
electroosmotic flow, variance, EOF, plate number, coating, adsorption, microchip electrophoresis, capillary electrophoresis, mass spectrometry
in
Analytical Chemistry
volume
81
issue
1
pages
343 - 348
publisher
The American Chemical Society
external identifiers
  • pmid:19035645
  • wos:000262113400049
  • scopus:58149462262
ISSN
1520-6882
DOI
10.1021/ac8010457
language
English
LU publication?
yes
id
14845b2f-1e9b-42a2-9202-6903b361e115 (old id 1235324)
date added to LUP
2009-01-08 09:33:41
date last changed
2017-01-01 04:22:52
@article{14845b2f-1e9b-42a2-9202-6903b361e115,
  abstract     = {Miniaturization of analytical separation methods offers several advantages, including short run times, high resolution, and high recovery of the sample constituents. To optimize these parameters, the reversible adsorption (to minimize loss in resolution), as well as the irreversible adsorption (to minimize loss of analytes) must be quantified. However, no useful equation is available for the calculation of the variance of reversible adsorption. Therefore, we have taken another approach to quantify the reversible interaction. The method is unique and important since no equation for calculation of this variance is required. Instead, two experiments are required, which are run under such conditions that the variance of a certain parameter has the same numerical value in the two experiments (one with and without EOF), except for the variance of reversible adsorption. The approach is universal in the sense that it can be used for many different mathematical concepts and be modified to also cover certain functions other than a sum of parameters. We have also introduced a simple expression for the irreversible adsorption, which shows that the hydrophobic interaction from only two methyl groups in the coating gives rise to as much as 40-50% loss of protein, and the width of the zones in the capillary with this coating was 8-15% larger compared to the zone width in the polyacrylamide-coated capillaries. The reproducibility in migration time, peak area, and peak width in two consecutive runs in capillaries with two methyl groups in the coating was very low, but in EOF-free polyacrylamide-coated capillaries extremely high, indicating that the reversible and irreversible adsorption of proteins to this coating is negligible. The scanning detector, frequently used in free zone electrophoresis in the 1960s-1970s, gives true separation parameters and is, therefore, much preferable to the stationary detector used in most CE experiments, because this detector gives apparent separation parameters.},
  author       = {Farkas, Viktor and Rezeli, Melinda and Végvári, Ákos and Kilár, Ferenc and Hjertén, Stellan},
  issn         = {1520-6882},
  keyword      = {electroosmotic flow,variance,EOF,plate number,coating,adsorption,microchip electrophoresis,capillary electrophoresis,mass spectrometry},
  language     = {eng},
  number       = {1},
  pages        = {343--348},
  publisher    = {The American Chemical Society},
  series       = {Analytical Chemistry},
  title        = {General approach for certain quantitative calculations for Instance of the variance of reversible adsorption to the capillary wall in CE},
  url          = {http://dx.doi.org/10.1021/ac8010457},
  volume       = {81},
  year         = {2009},
}