General, chemical type or category of compound to be separated.
The type of resin that is packed inside the column tube.
United States Pharmacopeia HPLC column designation.
Size (in micrometers) of the polymer or silica bead packed inside the column tube.
Inside diameter (in millimeters) of the column tube.
Length of the column tube (in millimeters).
Hamilton HxSil C18 columns exhibit greater retention than most columns. This allows the separation of compounds that are not sufficiently retained on other C18 columns. Figures 1 and 2 illustrate the separation of polycyclic aromatic hydrocarbons (PAH’s) on an HxSil C18 column versus a Nova-Pak® C18 column of the same length. The flow rate has been reduced for the Nova-Pak C18 column to compensate for the smaller I.D. The Hamilton HxSil C18 column provides about twice the retention for these compounds (23 minute run time versus 11 minutes). The greater retention of the HxSil C18 column provides better separation of these PAH compounds. With the HxSil C18 column, peaks 2 through 6 (naphthalene, acenaphthylene, acenaphthene, phenanthrene, anthracene) are baseline resolved. The Nova-Pak C18 column does not fully separate peaks 2 and 3; peaks 5 and 6 are only partially resolved. Peaks 9 and 10 are better separated on the Hamilton HxSil C18 column.