Abstract
In this article, we describe the analysis of aptamers for Hg^2+^ ions through CE with LIF (CEβLIF) detection using 2% poly(ethylene oxide) solutions containing OliGreen (fluorophore). In the presence of an EOF, DNA strands migrating against the EOF were detected at the cathode end. Four DNA strands β T~33~, T~5~C~28~, T~5~C~5~T~23~, and T~15~C~5~T~13~ β could not be separated through CEβLIF in the absence of Hg^2+^. At 0.3βmM Hg^2+^, however, all four were partially separated within 20βmin, with SDs of the migration times all being less than 2.5%. From the CE, fluorescence, and ellipticity data, we concluded that the conformations of these four DNA strands all changed from randomβcoil to folded structures as a result of TβHg^2+^βT bonding. In addition, we found that this CE approach provided different electropherograms patterns for T~7~, T~15~, and T~33~ in the absence and presence of Hg^2+^, indicating various interactions of the DNA strands with Hg^2+^. Using this simple, highβresolution CE approach, we also demonstrated that adenosine triphosphate has a stronger interaction with the adenosine triphosphate aptamer than with either the plateletβderived growth factor aptamer or T~33~. This CE approach holds great potential for screening aptamers for small solutes, studying the catalytic activity of DNAzymes, and evaluating the biological functions of microRNA.