To Erics**, That is a "no ending" topic if you allow me to elucidate: once a man walk into bar. (Just my 2 cents)
Precursor Ion Scan: (select a specific m/z in Q3)
Scan Q1, obtain all the precursor ions which could product the specific m/z ion in Q3.
Q1 masses Q3masses
from to from to 300 (m/z) or 400 (m/z) to the same -> 191 (m/z).
Neutral Loss Scanning: perform Q1 and Q3 at the same time.
The only different is that always keep a specific mass different
(the m/z is neutral loss)
Could locate the precursor ions that could product ions of neutral loss.
Q1 masses Q3 masses: from to from to
200 (m/z) -> 182 (m/z): loss 18 (m/z)
420 (m/z) -> 402 (m/z): loss 18 (m/z)
is good for identification of some functional groups ( -OH, -NH2)
So for Q-TOF: it is MS-MS too, but different Q-Q. The 1st MS is a Quadruple, the 2nd mass is TOF.
As I said above, neutral loss scanning requires the 100% exact same scan mechanism happening in 2nd mass. Simultaneous scan at the same ion:
The 1st mass for M, the 2nd mass is for M-m.
Separately Quadruple and TOF could not do that at the same time.
For both of them, MS1 full scan is not necessary: Full scan is only basic scan process, is not a requisite for all the neutral loss scanning and precursor ion scan.
For example, for product ion scan process: Q1 would allow you choose the specific m/z precursor ions, (just change RF/DC is ok), then Q2 CID, Q3 is for product ions scanning.
