In‐line coupling SPE and CE for DNA preconcentration and separation

Abstract

An in-line SPE method coupled to CE was developed for the analysis of DNA. The amino silica monolith was prepared in situ by polymerization of tetraethoxysilane and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane in ethanol aqueous solution at the inlet end of a 100 μm id fused-silica capillary, and the remaining part of the capillary was used as separation channel. The procedure for this in-line SPE-CE method was constructed on the basis of investigation on operational conditions such as the introduction mode of sieving matrix, the composition of elution solvent and the elution time. Twenty millimolar ammonium hydroxide was demonstrated to be effective for DNA desorption from the monolith, and linear poly(N-isopropylacrylamide) was used as the separation matrix. The proposed method could achieve limits of detection of 0.065-0.123 ng/mL for six DNA fragments ranging 100-2000 bp. Compared with conventional CE, preconcentration factors of over 100 times were obtained. The applicability of the in-line SPE-CE method was further demonstrated by analyzing plasmid DNA from Escherichia coli crude lysate.

On-chip DNA preconcentration in different media conductivities by electrodeless dielectrophoresis

“…6. It indicated that the concentration was magnified near 5 times in 10 s. Compared to in-line preconcentration method 11 (100 times in 40 min) and on-chip polymerase chain reaction (PCR) 27 (40 cycles in 108 min), the proposed method is quick enough to increase DNA concentration for analytic and detection purpose. It is noted that the preconcentration of DNA in this high conductive solution is achieved by p-DEP.…”

“…However, it is too specific for DNA molecules with a certain length due to its fixed pore size. Chemical method, 10,11 based on absorption and desorption processes, is another conventional way to enhance DNA concentration, prior to capillary electrophoresis (EP). Electrical method is the most popular technique due to its simple implementation and reliability.…”

Recent applications of CE‐ and HPLC‐MS in the analysis of human fluids

“…Among systems that have been applied to human body fluids, that described by Feng et al. is noteworthy. They constructed “in situ” an amino silica monolithic column that was applied to develop a method for the sensitive analysis of DNA fragments.…”

Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2010–2012)

“…The pre‐concentration factor of about 250‐fold was obtained in the 2 h fully automated process. Feng et al combined SPE with CE for the separation of DNA fragments by CSE . An amino silica monolith, prepared in situ by polymerisation of tetraethoxy‐silane and N ‐(β‐aminoethyl)‐γ‐aminopropyltriethoxysilane in EtOH at the inlet of the capillary was used as the SPE column.…”