Merck HPLC Columns

Merck Chromolith HPLC columns

Merck Chromolith HPLC columns are made from highly porous monolithic rods of silica with a bimodal pore structure. The column is no longer packed with small particles but instead consists of a single piece of high-purity silica gel. This enables a separation speed four times faster than with a standard particulate column. Additional advantages of Chromolith columns are a longer lifetime and lower matrix sensitivity with biological samples. Multiple Chromolith columns coupled together provide separation efficiencies of 100,000 plates/column at normal pressure.

Merck Purospher columns

Besides highly efficient Chromolith columns, Merck Millipore columns are available in frequently used materials such as LiChrosorb, LiChrospher und Superspher. Further various special sorbents such as Aluspher and diverse chiral phases are available, e.g. Purospher and Purospher STAR. These columns are based on pure silicia without metal.

Merck Superspher HPLC Columns

Superspher is a high performance spherical silica carrier with a particle size of  4µm, providing an excellent pressure / separation performance ratio. The separation peformance of Superspher columns typically is 100,000 N/m. A broad range of modifications on Superspher are available: reversed phase derivatives (RP-8, RP-18 endcapped, RP-18, RP-18 endcapped and RP-select B) and polar derivatives (Si 60). Superspher sorbents are packed in LiChroCART cartridges in different lenghts and internal diameters. To operate with LiChroCART cartridges, the cartridge holder manu-CART has to be used.

Merck ZIC-HILIC and ZIC-pHILIC - for HPLC Separation of Polar Compounds

The ZIC-HILIC column is the ideal choice for separation of polar and hydrophilic compounds as it is truly orthogonal to reversed phase chromatography (RPLC) columns. Analytes such as amino acids, peptides, carbohydrates, plant extracts and various other polar compounds that usually have little or no retention and may be affected by wettability problems in RPLC, generally have strong retention on the ZIC-HILIC column.

The zwitterionic ZIC-HILIC stationary phase is attached to porous silica and is available in columns from capillary to preparative dimensions. The separation is achieved by a hydrophilic partitioning mechanism superimposed on weak electrostatic interactions. Typical eluents contain a high content of an organic solvent (e.g. acetonitrile) mixed with buffer, i.e., comparable to RPLC eluents, however, water being the strong solvent. Also, the low content of water in the eluents enables higher detection sensitivity in many LC/MS applications.