Question concerning the RT and RI in MS-DIAL

July 17, 2020, 05:06:20 PM

Hello everyone,

I have a question concerning the Retention Time and Index in MS-Dial compared to ChromaTOF:

I process Leco BT-TOF accurate GC-MS data. For testing I loaded 5 Quality Controls with increasing concentration. The Peaks are found, integrated and aligned really nicely!

But when I check the peaks in ChromaTOF I dont find any of them at those times. So I looked for my Internal Standard, and when I have a look at the EIC in my blank, there is one nice peak with 361 at 16.7 minutes (the Internal Standard). Yet when I check the time for the peak in ChromaTOF it says 1250 seconds, which would translate to 20.833 minutes.

When I have a look at the Retention Index it says 1890 in MS-Dial, and 2292 in Chromatof, calculated with the same Kovats-RI List.

The files were directly exportet as mzml in centroid mode from Chromatof and then transformed to abf. No Retention Time cutting was performed.

I hope my question is somehow clear and somebody has an Idea what setting I chose wrongly!

All the best,
and thank you a lot!
Martin

Re: Question concerning the RT and RI in MS-DIAL

Reply #1 – August 13, 2020, 11:10:57 PM

Hi Martin,

sorry for this delay. Actually, I am not sure for the reason.
1. did you check the retention times of mzML file? If the RT is changed at this stage, it's difficult to reproduce the RT values in the MS-DIAL side.
2. did you try to use cdf file format for MS-DIAL processing?

Thanks,

Hiroshi