2.5 Mass Spectrometry
41
2.5 Mass Spectrometry
41
Mass Ion
Product ion
(and neutral
particle lost)
Substructure or compound type
33
CH 3 OH 2
+ ,
SH + , CH 2 F +
[M-33] +
(SH)
nonspecific (with isotope signal for
34 S)
S indicator
(CH 3 + H 2 O) nonspecific
O indicator
(CH 2 F) fluoromethyl
34
SH 2
+·
[M-34] +·
(SH 2 ) nonspecific (with 34 S isotope signal)
S indicator
(OH + OH) nitro compounds
35
SH 3
+ , Cl +
[M-35] +
(Cl) chloro compounds (with 37 Cl isotope
signal)
(OH + H 2 O) nitro compounds
2 × O indicator
36
HCl +· , C 3
+
[M-36] +·
(HCl) chloro compounds
(H 2 O + H 2 O)
2 × O indicator
37
C 3 H +
37 Cl +
chloro compounds (with isotope
signal for 35 Cl)
38
C 3 H 2
+·
39
C 3 H 3
+
[M-39] + (C 3 H 3 ) aromatics
K +
[M+39] +
in ESI spectra often strong even if
K + is only an impurity (with isotope
signal for 41 K)
[M-39] +
in ESI spectra of organic K + salts
40
C 3 H 4
+· , Ar +· ,
CH 2 CN +
[M-40] +·
(CH 2 CN) cyanomethyl
41
C 3 H 5
+ ,
CH 3 CN +·
[M-41] + (C 3 H 5 ) alicyclics (especially polyalicyclics),
alkenes
(CH 3 CN) 2-methyl-N-aromatics, N-methylanilines
42
C 3 H 6
+· ,
C 2 H 2 O +· ,
CON + ,
C 2 H 4 N +
[M-42] +· (C 3 H 6 )
(C 2 H 2 O)
nonspecific; abundant: propyl
esters, butyl ketones, butylaromatics,
methylcyclohexenes
acetates (especially enol acetates),
acetamides, cyclohexenones,
α,β‑unsaturated ketones
43
C 3 H 7
+ ,
C 2 H 3 O + ,
CONH +·
[M-43] + (C 3 H 7 )
nonspecific; abundant: propyl,
alicyclics, cycloalkanones,
cycloalkylamines, cycloalkanols,
butylaromatics
(CH 3 CO) methyl ketones, acetates, aromatic
methyl ethers