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Gas chromatography

In gas chromatography (GC), the mobile phase is always a gas, mostly either He, N2 or H2. The stationary phase is often a viscous, gum-like liquid adhered to the inner wall of a capillary column (WCOT = Wall Coated Open Tubular). Transport of the components (analytes) occurs exclusively in the mobile phase, while separation only takes place in the stationary phase. The quality of a separation (resolution) depends on the residence time of the components within the stationary phase and on the rate of interactions. The type of interaction between component and phase (selectivity) is determined by the functional groups of the stationary phase. The polarity of the phase is a function of its substituents.

GC columns

MACHEREY-NAGEL produces more than 50 GC phases. Most of them are USP listed. Each column is individually tested and supplied with test certificate (incl. test chromatogram) and instruction leaflet, but without fittings or ferrules. Columns have fused ends or are sealed with septa, to protect them from atmospheric oxygen. The standard size of a GC cage is 7 " (inch). In addition to the standard program we can often also offer custom-made columns (further dimensions, with integrated guard column, supplied on a 5 inch (5 ", ~13 cm) cage e.g., for the Agilent GC 6850. etc.).

Accessories for gas chromatography

Addtional to GC columns and derivatization reagents we also offer GC pre-columns (guard columns) and retention gaps, ferrules, capillary connectors and septa as well as general accessories and tools.

Gas Chromatography