Insights into the Partitioning of DNA in Aqueous Biphasic System Containing Ammonium-based Ionic Liquid and Phosphate Buffer

Abstract

Aqueous biphasic system (ABS), as an efficient separation process, can be applied in the extraction and purification of DNA which is an integral part of life science studies. Ammonium-based ionic liquids (ILs) were synthesized, and ABS formation was evaluated with phosphate buffer [K2HPO4-KH2PO4 (1.82:1.00)] as the second phase forming component. The structural influences of the cation of ILs, including alkyl chain length and the effect of functional groups on phase formation, were methodically assessed. The experimental binodal data were correlated with Merchuks’ equation and showed adequate fitting. The constituents of ABS were carefully selected to obtain a biocompatible system with controlled pH to use for the partitioning of biomolecules. The proposed system was applied in model DNA partitioning and resulted in a single step, highly efficient extraction at 298.15 K. The structural variations of the selected ILs influenced the partitioning, and thus, ABS containing benzyltributylammoniumchloride ([BTBA]Cl) IL was found to be efficient among the studied systems. Furthermore, the partition conditions were optimized in terms of the concentrations of IL and buffer using [BTBA]Cl/K2HPO4-KH2PO4 (1.82:1.00)/water system. Finally, the extraction mechanism involved in the partitioning and stability of DNA was investigated through FT-IR and circular dichroism spectra.