TITLE

Sequential preconcentration by coupling of field amplified sample injection with pseudo isotachophoresis—acid stacking for analysis of alkaloids in capillary electrophoresis

AUTHOR(S)
Zhao-Xiang Zhang; Xiao-Wei Zhang; Jing-Jing Wang; Shu-Sheng Zhang
PUB. DATE
March 2008
SOURCE
Analytical & Bioanalytical Chemistry;Mar2008, Vol. 390 Issue 6, p1645
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
A novel on-column sequential preconcentration method based on the combination of field-amplified sample injection induced by acetonitrile and pseudo isotachophoresis (ITP)–acid stacking is developed for simply but efficiently concentrating alkaloid cations in a high-salt sample matrix in capillary electrophoresis. Acetonitrile (70%) added to a sample solution with a high-salt sample matrix not only induces field-amplified sample stacking by decreasing conductivity but also acts as a termination reagent in the succeeding pseudo ITP. After sample injection had been completed, a plug of H+ was injected electrokinetically and a neutralization reaction between H+ and tartrate from the buffer solution produced a low conductivity zone, in which the injected analyte cations were further concentrated. With the sequential preconcentration method, a 3 orders of magnitude detection sensitivity (1,400-fold) increase could be observed compared with the conventional electrokinetic injection method, without compromising separation efficiency and peak shape, and detection limits of 0.1 ng/mL for myosmine and 0.3 ng/mL for anabasine with the conditions selected were achieved. The calibration curves demonstrated good linearity in the concentration ranges 1.3–600 ng/mL for myosmine and 4.9–900 ng/mL for anabasine, respectively. The proposed method has been used to analyze successfully trace alkaloids in cigarette samples. [Figure not available: see fulltext.]
ACCESSION #
31342609

 

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