In order to select the proper liner, you must first know your application needs:
- Split injection is typically used for samples that are dirty and/or have a broad range of analyte concentrations. Split injection must quickly and completely vaporize the sample into a homogenous cloud, and there are numerous liner designs that achieve this. The most common is the straight tube packed with fused silica wool. Alternate designs include the laminar cup, frit splitter, cup splitter, cyclo, baffle splitter, and mini-Lam splitter, all of which are designed to facilitate rapid, homogenous vaporization; yield reproducible performance; and minimize molecular weight discrimination.
- Splitless injection is typically used for trace-level analyses. Generally, the liner should have a taper design (single, double, or recessed) to help contain the vapor cloud in the liner during the extended hold time and to minimize the breakdown of compounds sensitive to catalytic decomposition from contact with metal inlet surfaces. The single taper design is used with a single column; the recessed design can be used for a dual-column application. Both are routinely packed with fused silica wool.
- Direct injection liners connect the column to the bottom of the inlet sleeve. This allows the sample to be swept directly into the column, eliminating injection port discrimination and sample contact with hot metal surfaces. Direct injection liners are available for packed column or capillary splitless injectors. We recommend a drilled Uniliner inlet liner for capillary split/splitless injection ports.
All liners, regardless of application, should always be deactivated. We also recommend that, whenever possible, they be packed with deactivated glass or fused silica wool to facilitate uniform sample vaporization and trap nonvolatile residue, thereby preventing column contamination.
