Liner represent an indispensable element for a proper functioning of the GC system. They allow an injected liquid sample the transition to the volatile phase and then into the GC column. The elevated temperature in the inlet vaporizes the liquid sample for transfer to the head of the GC column. The result is a significant change in the volume during the phase transition - the volume of the resulting vapor has to remain within the volume of the liner. If the expansion volume is too large, the sample can be lost, resulting in a poor reproducibility and sensitivity and this may lead to carryover the entire GC system.
The selection of a suitable liner for your GC system is, however, often not very simple but very important. The key aspects you should consider are the following:
- Liner ID and geometry
- Type of injection
- Packing materials of the liner
- Treatment or deactivation of the liner
1. Liner ID and geometry
Different liner IDs are indicators of varying volumes. A number of factors affect or reduce the effective volume of a liner, for example:
- taper, baffles and other liner features
- packing materials
- carrier gas
In general the vapor cloud formed by the sample should not exceed half of the total volume of the liner. The expansion volume of solvents limits the injection volume. Solvents with low density and high molecular weight are desirable - this increases the volume of the solvent which can decrease the injected and detection limits.
2. Type of injection
Another key aspect in the selection of a suitable liner is the type of injection. Split liner allow the split flow over the bottom of the liner and causes a removal of a portion of the sample. This allows the implementation of a split injection. A selection of split liner you can find here.
Splitless Liners are usually tapered at the bottom. This helps to convey the sample to the column and minimizes sample contact with reactive metal components in the inlet during injection.
3. Packing material of the liner
The active sites of Inlet liners can adsorb sample components and cause peak tailing. This can lead to a loss of sensitivity and reproducibility. Active sites may also cause deterioration in certain classes of compounds.
4. Deactivation / treatment of the liner
In the Analytics-Shop users can choose from a wide range of liners from numerous manufacturers. These high quality liners offer a significantly improved inertness for a wide range of compounds. With various deactivation processes they often provide enhanced transferring the sample to the GC column, resulting in increased accuracy and precision in the analysis itself. This allows lower detection limits for some agents.
In our offer you will find a wide range of high quality liners and any other accessories for the (gas) chromatography. Questions about our products? Our expert team will be happy to advise you.
When the liners are not exchanged in regular intervals, this can lead to huge problems. Firstly, a used liner cannot guarantee consistent reproducibility, which could affect the entire GC system. Furthermore, the liner should be replaced from time to time in order to avoid degradation of the peak shape and sample disintegration. So-called "ghost peaks" can also be a result of liners that haven't been exchanged in too long.
Sky Inlet Liners increase accuracy and reproducibility with state-of-the-art deactivation. These liners achieve lower detection limits for a wide range of active compounds. The innovative deactivation used for Sky liners leads to exceptional inertness for a wide range of analyte chemistries. By reducing active sites and enhancing analyte transfer to the column, these liners increase accuracy and precision, allowing lower detection limits for many active compounds. Also fewer liner changes are needed and less downtime for maintenance.