0000000000814324
AUTHOR
N. Von Doehren
Comparative study on the column performance of microparticulate 5-μm C18-bonded and monolithic C18-bonded reversed-phase columns in high-performance liquid chromatography
In this paper we report on the results of a comparative study on the performance of Purospher RP 18e, 5 μm, columns and prototypes of monolithic columns named SilicaROD from Merck, Darmstadt, Germany. The studies were performed on HPLC equipment with minimum extra column contribution. The plate height linear velocity dependency of the Purospher RP 18e column showed a minimum of H of about 10–15 μm at a linear velocity of 1 mm/s. The H versus u curves of the monolithic columns followed the same course. Yet, the curves remained flat up to a linear velocity of about 7 mm/s, where the Purospher RP 18e column could not be operated anymore due to the extremely high back-pressure. In conclusion th…
Towards the ultimate minimum particle diameter of silica packings in capillary electrochromatography.
Porous silica beads with an average particle diameter between 0.2 and 3 microm have been applied as packing material in capillary electrochromatography (CEC). The experiments were directed to investigate whether it is really feasible and as promising as expected to use such small particles. In CEC, plate heights of H approximately/= 1-2 d(p) can be achieved which is smaller than the plate heights usually attained in high-performance liquid chromatography. Using a capillary packed with 0.5 microm silica beads we achieved a plate height of H = 3 d(p) indicating the presence of dispersive effects like Joule heating. Calculations demonstrate that at a field strength of about 800 V cm(-1) one th…