Page 217 - Shimadu Consumables Catalog

GC Glass Insert

The GC inlet functions as the interface between the syringe and the GC capillary column, where the sample is introduced,
vaporized, mixed with carrier gas and transferred to the column. Shimadzu instruments offer several types of inlets - split, splitless,
programmable temperature vaporization (PTV) and on-column.
The glass insert prevents the sample contacting the metal walls of the injector block. Glass insert geometry and packing materials
enable the glass insert to achieve greater heated surface area; this additional surface area can often improve sample vaporization.
Conversely, choosing the wrong glass insert geometry can significantly decrease the reproducibility and quality of analysis.

Injection Technique Sample Types Glass insert Geometry Function
A bottom taper focuses sample onto the head of
the column and minimizes sample contact with
Taper
metal parts of the inlet. The addition of quartz
Trace Level Analyses/ wool to your glass insert promotes mixing of
Splitless
Active Compounds analytes, aids the vaporization of liquid samples,
and works as a trap to collect non-volatile residue
in the sample (i.e. protects capillary column from
‘dirty’ samples).
Ensures quartz wool remains in the correct position
FocusLiner™
General Purpose/ in the liner. Excellent reproducibility results from
Split Concentrated Samples/ the wiping of the sample from the syringe needle
Dirty Samples and the prevention of droplet formation. Minimiz-
es high molecular weight discrimination.
Bottom taper focuses sample onto the head of the
Taper FocusLiner™ column and minimizes contact with metal parts of
Trace Level Analyses/
Splitless Dirty Samples/ the inlet. Excellent reproducibility results from the
Wide Boiling Point Range wiping of the sample from the syringe needle and
the prevention of droplet formation. Minimizes
high molecular weight discrimination.
Direct Taper Direct glass inserts facilitate maximum transfer of
Trace Level Analyses/ sample by connecting directly to the GC column
Direct
Active Compounds and inhibiting sample degradation due to hot
metal components inside inlet.
General Purpose/ Straight glass inserts facilitate higher split flows.
Concentrated Samples/ Straight Narrow bore straight glass inserts facilitate fast
Dirty Samples (only if GC work. Small injection volumes of less than 0.5
Split/Splitless
quartz wool is present)/ μL are best used with a narrow bore. Narrow bore
Gaseous Samples (also straight glass inserts improve focussing of gaseous
purge & trap, headspace) samples (purge, trap & headspace).
Glass Insert Deactivation

Every batch of glass inserts are tested for inertness using the EPA 8081B method. This standard method ensures that each batch of
glass inserts has less than 3 % Endrin breakdown from a 1 ppm injection.

Pg C-67