title: Mixed-mode hydrophobic ion exchange for the separation of oligonucleotides and DNA fragments using HPLC.
abstract: Hydrophobic anion exchangers were formed by cobonding both ionic and hydrophobic ligands to silica gel. These phases were used to separate single-stranded oligonucleotides and double-stranded DNA restriction fragments. By varying the ratio of n-octyldimethylsilane and either 3-chloropropyldimethylsilane or 4-chlorobutyldimethylsilane added during silanization a series of mixed-ligand or mixed-mode stationary phases was created. Concentration and ratio of bonded ligands were determined using a new gas chromatography fluorination method. Total ligand coverage was found to approach 2.1 ligands nm-2 for n-octyldimethylsilane. Bonding reproducibility for mixed-mode phases was good. Nucleic acid separations were achieved under gentle mobile phase conditions by using the stationary phase as an easily modifiable variable.
mesh_terms: D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002852:Chromatography, Ion Exchange; D004247:DNA / Q000302:isolation & purification*; D004262:DNA Restriction Enzymes; D004277:DNA, Single-Stranded / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008024:Ligands; D009841:Oligonucleotides / Q000302:isolation & purification*
chemical_list: D004277:DNA, Single-Stranded; D008024:Ligands; D009841:Oligonucleotides; D004247:DNA; D004262:DNA Restriction Enzymes