1. Purification of anionic fluorescent probes through precise fraction collection with a two‐point detection system using multiple‐stacking preparative capillary transient isotachophoresis
- Author
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Shingo Saito, Miyauchi Saori, Tomoko Haraga, Hiroto Tsujimura, Takuya Kamimura, and Masami Shibukawa
- Subjects
Anions ,Chromatography ,Isotachophoresis ,Aptamer ,Ligand binding assay ,010401 analytical chemistry ,Clinical Biochemistry ,Stacking ,Electrophoresis, Capillary ,02 engineering and technology ,Fractionation ,Aptamers, Nucleotide ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,Fluorescence ,0104 chemical sciences ,Analytical Chemistry ,chemistry.chemical_compound ,chemistry ,Reagent ,Fluorescein ,0210 nano-technology ,Fluorescent Dyes - Abstract
A novel combination of CE-based separation techniques was used for the precise fractionation of ionic compounds from impurities. The combination of on-capillary concentration and separation using transient isotachophoresis, with multiple injections and a two-point detection system provided higher efficiency, and accuracy at a microliter-scale injection volume, than when CE was individually used for purification. In this paper, we present successful applications of the CE fractionation techniques for the purification of fluorescein, fluorescein-4-isothiocyanate, two fluorescent metal ion probes, and a fluorescein-modified DNA aptamer. The purity of the isolated fluorescent probes ranged from 95 to 99%. Such high purity could not be achieved using chromatographic purification techniques. With relatively low dilution factors of 6-9, the purified probe solutions were practical for use as purified stock solutions. In addition, the fluorescein-modified DNA aptamer purified by our method was successfully used in a thrombin binding assay. The method developed was useful for the purification of anionic fluorescent reagents to be of ultratrace analytical grade for use with CE-LIF.
- Published
- 2020