Merck columns come in three formats.

1. The Hibar® RT is a traditional column with standard ¹/₁₆" female end fittings. The Hibar® stand-alone guard cartridge holder, in conjunction with the LiChrospher® 4-4 guard cartridges, can be used to protect the column.

2. The LiChroCART® cartridge columns utilise the manuCART® removable end fittings, which have standard ¹/₁₆" female connections. ManuCART® end fittings incorporate a guard cartridge holder as an integral part of the assembly which minimises dead volume. It can be used with any Merck column between 75 and 250 mm in length.

3. Chromolith® columns - monolithic silica rods are clad in PEEK and are in ready to use format with end fittings, see relevant catalogue entry for details and pictures of columns and guard columns.

LiChroCART® cartridge with LiChroCART® pre-cartridges and coupling kit: Connecting a LiChroCART® cartridge with LiChroCART 25-4 and 25-2 pre-cartridge with coupling kit.
LiChroCART® cartridge with manuCART® end fittings: The manuCART® system incorporates a guard cartridge holder which will take 2, 3 and 4 mm I.D. columns with lengths from 75 to 250 mm.

Guard cartridges: Merck 4-4 mm pre-columns or guard cartridges offer excellent value. With the appropriate holder they can be used with both Merck and non Merck columns. Use the ManuCART® integral fittings for Merck cartridge columns and the Hibar® 4-4 pre-column holder for end-fitted columns. Merck 4-4 guard cartridges are available in C18, C8 RP Select B, Si, NH₂, CN and DIOL phases.