On-line sample preconcentration by sweeping with dodecyltrimethylammonium bromide in capillary zone electrophoresis

Abstract

On-line sample preconcentration of oligonucleotides with a new sweeping carrier was developed by using dodecyltrimethylammonium bromide (DTAB) below the critical micelle concentration (CMC). The sweeping results with DTAB below and above the CMC were compared. The use of DTAB below the CMC benefits the preconcentration of the oligonucleotides, while the use of DTAB above the CMC is good for hydrophobic small molecules. The factors affecting the sweeping results were optimized and this method was evaluated by constructing calibration curves for thrombin aptamers. The sweeping scheme produced a 112-fold sensitivity enhancement for the oligonucleotides relative to that run in a running buffer without DTAB. The sweeping method developed here can be a good reinforcement of the preconcentration scheme by sweeping when less-hydrophobic analytes or large negatively-charged molecules need to be preconcentrated.

Continuous Signal Enhancement for Sensitive Aptamer Affinity Probe Electrophoresis Assay Using Electrokinetic Concentration

“…Various schemes that combine sample concentration and CE analysis have been reported previously, including sample sweeping 8 , preconcentration using a size-exclusion membrane 7 , transient isotachophoresis (t-ITP) 13 , and temperature gradient focusing (TGF) 14 . In the first two cases, preconcentration and separation are carried out sequentially, thus band broadening during separation reduces the sensitivity enhancement.…”

Screening and confirmatory methods for the analysis of macrocyclic lactone mycotoxins by CE with amperometric detection

“…For this purpose, an improvement in the attained sensitivity with the former separation scheme was needed. On‐column sample preconcentration strategies were proved to be an important way to attain lower detection limits in CE by the introduction of large sample plugs and subsequent stacking 23 or sweeping 24 of the target analytes into a narrow zone. Taken into account that one of the main objectives of this work was an amenable connection of SFE sample treatment with the analytical separation by CE without introducing any conditioning or preconcentration step, SFE extracts were kept intact.…”

Highly sensitive detection of melamine and its derivatives by capillary electrophoresis coupled with online preconcentration techniques

“…The presence of water plug and HCB during the long CSEI step was proved to be favorable to the improvement of the total focusing effect [38,41,46]. Moreover, the water plug could improve the reproducibility [47].…”