Split-Vent Traps: GC’s Dirty Secret
November 1st 2015In gas chromatography (GC) split injection systems, as much as 99% or more of the injected sample never enters the column: It is released downstream of the inlet where it can encounter and possibly perturb precision gas control devices. The split-vent trap acts to prevent or at least moderate such effects. This month’s instalment addresses the operation and maintenance of split-vent traps.
Retention and Selectivity of Stationary Phases Used in HILIC
November 1st 2015Hydrophilic-interaction chromatography (HILIC) is a complex system involving partition, polar, and ion‑exchange interactions. Method development can be greatly facilitated by understanding the interactions that the different stationary phases provide and applying that knowledge to the separation task at hand. Through an understanding of the main differences of the set of analytes to be separated, a column or set of columns can be judiciously chosen to screen for effective retention and selectivity.