-
- Posts: 1
- Joined: Wed May 20, 2020 10:56 am
what is the transition of the internal standard 13C isotope?
Discussions about GC-MS, LC-MS, LC-FTIR, and other "coupled" analytical techniques.
roelio wrote:
I use internal standards for an lcms method. Now I want to know the transitions without having to tune them in the LCMS, they are very expensive. And we don't have a lot of volume. I know you can calculate it by knowing the transitions of the normal component. How do you calculate that? For example Aflatoxin B1 313.3 -> 241.1 and 285.1
what is the transition of the internal standard 13C isotope?
lmh wrote:
… as a general rule, if you aren't sure of the fragment, and the standard is ludicrously expensive, you still don't have to repeat the tune. There are two cheap and easy alternatives:
(1) do a chromatography run with a little bit of internal standard, and an MS2 method with a scan across the region where you expect the product ions (using the collision energy that you already optimized with the unlabeled analyte). Check what the products are, or...
(2) if the standard is so expensive that you can't inject enough to see in scan mode, set up MRMs. Say your internal standard is mass +5, set up MRMs for the fragment you see from unlabeled analyte, and +1, +2, +3, +4, +5, and see which MRM gives you the biggest peak in a chromatography run of internal standard alone. Then delete the transitions you didn't need.
roelio wrote:
I use internal standards for an lcms method. Now I want to know the transitions without having to tune them in the LCMS, they are very expensive. And we don't have a lot of volume. I know you can calculate it by knowing the transitions of the normal component. How do you calculate that? For example Aflatoxin B1 313.3 -> 241.1 and 285.1
what is the transition of the internal standard 13C isotope?
fainabuff wrote:roelio wrote:
I use internal standards for an lcms method. Now I want to know the transitions without having to tune them in the LCMS, they are very expensive. And we don't have a lot of volume. I know you can calculate it by knowing the transitions of the normal component. How do you calculate that? For example Aflatoxin B1 313.3 -> 241.1 and 285.1
what is the transition of the internal standard 13C isotope?
I also have same query Mymorri..
Separation Science offers free learning from the experts covering methods, applications, webinars, eSeminars, videos, tutorials for users of liquid chromatography, gas chromatography, mass spectrometry, sample preparation and related analytical techniques.
Subscribe to our eNewsletter with daily, weekly or monthly updates: Food & Beverage, Environmental, (Bio)Pharmaceutical, Bioclinical, Liquid Chromatography, Gas Chromatography and Mass Spectrometry.