GLYP and AMPA: Positive mode ESI LC-MS of FMOC-AMPA gave a protonated molecule
at m/z 334 from which a product ion at m/z 179 (fluorenyl methylium) was formed via neutral loss of AMPA (-111 Da) during CID (Fig.
The mass spectrometer was operated in positive electrospray ionization ([ESI.sup.+]) mode and the protonated molecule
[[M + H].sup.+] was monitored in multiple reaction mode (MRM) .
M1 and M1' showed their protonated molecule
ion [[M + H].sup.+] at m/z 946.4512 and m/z 946.4513 in positive ion mode, respectively; both of them matches the elemental composition of [C.sub.44][H.sub.60][N.sub.5][O.sub.16]S.
The inhibitor influences the redox electrochemical process, affecting the cathodic regions of the steel surface through chemical interaction involving the protonated molecule
in the acid solutions.
Metabolite M1 (MRM 488-312) was eluted at the retention time of 4.9 min, showing protonated molecule
ion at 488 Da, which is 176 Da more than that of parent.
Software reduces the complex data set to a short list of peaks for further review, interprets the spectrum to determine the mass of the protonated molecule
, and determines potential chemical formulae for the potential metabolite.
Detection of the MDA protonated molecule
[[M + H].sup.+] of m/z 73 was performed in the selected ion monitoring mode (SIR).
Peak at 5.63 min had similar UV absorption as quercetin (14), but protonated molecule
was 162 Da heavier than quercetin.
Collision-induced dissociation (CID) was performed on the isolated protonated molecule
using argon collision gas (7 psi) and nitrogen was used as desolvation and nebulizing gas (flow rates of 260 and 26 Lx[h.sup.-1], resp.).
(i) Degradation of the protonated molecules
of EP catalyzed by hydrogen ions ([k.sub.1])
These metabolites were named according to their m/z, and the metabolites with the same protonated molecules
were named according to the sequential order of their retention times.