on column
Posted: Fri May 30, 2008 1:10 pm
I have received a new 7890 gc and was wondering what "on column" is? I have a method that requires this. How can I check for it?
On-column can refer to one of two different injector situations: one for capillary and one for packed columns.
The capillary version is a special injector which allows a special needle to enter the column which is installed up inside the injector almost to the septum. The injector is not heated but may be allowed to track the temperature of the column oven. This injector is called a "cold on-column injector'.
The other on-column refers to a packed column injector. This has a packed column installed up into the injector almost to the septum and the standard manual syringe or autosampler needle deposits the sample inside the column which has a void space at the inlet side for this purpose. This inlet may or may not be heated, but it usually is at a higher temperature than the initial temperature of the column oven.
I hope this answers your query.
best wishes,
Rod