Glycerol-Enhanced Separation of DNA Fragments in Entangled Solution Capillary Electrophoresis

Abstract

(Hydroxyalkyl)methylcellulose additives to borate buffers have been used to create physically entangled solutions for fractionation of biological molecules by high-performance capillary electrophoresis, i.e., ESCE. We have observed that addition of glycerol to an entangled solution containing (hydroxypropyl)methylcellulose (HPMC) in Tris-borate buffer markedly improved the separation of double-strand DNA molecules ranging from less than 100 bp to about 1 kb by ESCE. This range of DNA fragment sizes is well suited to many PCR-based studies. We attribute the improved ESCE performance to the borate present in the buffer system. Borate can form dimeric 1:2 borate:didiol complexes with both glycerol and HPMC, acting as a central linkage to allow an entangled solution with different pore size to form chemically.