Qualitative and Quantitative Determination of Oligonucleotides by Non-Gel Capillary Electrophoresis

Abstract

A novel simple non-gel capillary electrophoresis (NGCE) method was developed for the qualitative and quantitative determination of oligonucleotides (ODNs). ODNs were synthesized in a DNA synthesizer and separated by NGCE under optimized conditions as follows: 25 mmol L⁻¹ Tris–boric–EDTA buffer (pH 8.0) with 7 mmol L⁻¹ urea in the presence of 20% (w/v) polyethylene glycol (PEG) 35000 at 30 °C and −20 kV. Single-base differences, in which there are differences in the base quantity and the single-base structure with the same base quantity, can be identified by the proposed method, and the quantitative determination was carried out. The obtained regression equation revealed a good linear relationship between the peak area ratio and the ODNs concentration. The correlation coefficient was 0.9986 and the relative standard deviation (RSD) of the precision was <3.6% (intro-day) and <6.2% (inter-day), respectively. The recoveries of three concentrations (high, middle, and low) were between 99.6% and 107.6%. The established method is sensitive, simple, economical, and can be used in gene mutation detection, pharmacokinetics study of nucleic acid drugs, and so on.