Column wall modifications using polyethylene oxide for capillary electrophoresis of ribonucleotides

In this study, a variety of fused silica capillaries with different combina tions and sequences of treatments with HMDS and polyethylene oxide were pre pared in order to develop an optimized column modification method for analy sis of ribonucleotides. The 12 most common ribonucleotides (UTP, CTP, ATP, GTP, UDP, CDP, ADP, GDP, UMP, CMP, AMP, and GMP) in human cells were used a s test solutes. Column performance measurements, including electroosmotic f low (EOF), solute migration speed and retention, column efficiency, peak sh ape, and resolution were investigated. By analyzing solute migration speed and retention of various hydrophilic/hydrophobic solutes, the column wall e ffects (EOF and adsorption) can be distinguished. This analysis method can give guidance in optimizing polymer coating properties (hydrophilicity/hydr ophobicity) for CE columns. By studying the performance of these columns af ter various surface treatments, we were able to improve the separation of r ibonucleotides from real samples to within 16 minutes with high efficiency and stability (over 300 analyses) using columns first deactivated with hexa methyldisilazane, and then coated with polyethylene oxide.