Chromatography Forum

First time posting, please forgive any etiquette errors.
I read the manual, searched the forum for this question, and emailed both the Thermo apps specialist and our service engineer with no answer yet (only 1 day, so far). So I thought I'd try here.
We are using a Triplus RSH on a new Trace1310. The instrument is set up with one injector going to a FID detector and the second injector going to an ISQ mass spec. We use Xcalibur v3.1 software.
We have set up one method successfully with injections going from 20mL headspace vials to the 1st injector and now I am beginning to set up a second method for injections from 2mL GC vials. In setting up the method, I noticed the default setting for "Sample Vial Depth" is 30mm. In the headspace vial method, we used a setting of 40mm, I don't know how we determined the 40mm was the correct value. It might have been a default or set by the service engineer during install and testing.
My question is "How do you determine the correct depth?" . It seems odd to me that the sample vial depth of the 20mL HS vials would be only 10mm different than the 2mL GC vials given the difference in size of the vials. Also, I'd like to understand how it works.
There is an option of "Bottom sensing" but without understanding exactly how it works, I'm hesitant to use it.
Thanks in advance, I've been lurking on the forum for a while and I appreciate everything I've learned.

I think I may have figured out a solution.
I took a spare syringe and inserted it through the septum of a vial until it was just above the bottom of the vial. I marked the syringe at the septum level with a marker and remove the syringe. Measured the length of the needle below the line. 31mm. So it appears to me that the default 30mm setting is reasonable. I guess I'll find out with my first injection.

The sample vial depth is not the depth of the vial itself, it is how deep the needle will penetrate the sample vial.

bottom sensing works fine, but it is not the best thing for the tip of thy needle. It can get slightly bend over time and will cause damage to the septum, so only use it if you don't have another option.

BMU