40
2 Summary Tables
Mass Ion
Product ion
(and neutral
particle lost)
Substructure or compound type
23
Na +
[M+23] +
in ESI spectra in the presence of Na + ;
sometimes strong even if Na + is only
an impurity
[M-23] +
in ESI spectra of organic Na + salts
24
C 2
+·
25
C 2 H +
[M-25] + (C 2 H) terminal acetylenyl
26
C 2 H 2
+· , CN + [M-26] +· (C 2 H 2 ) aromatics
(CN) nitriles
27
C 2 H 3
+ ,
HCN +·
[M-27] + (C 2 H 3 ) terminal vinyl, some ethyl esters and
N-ethylamides, ethyl phosphates
[M-27] +· (HCN) aromatic N, nitriles
28
C 2 H 4
+· , CO +· ,
N 2
+· , HCNH +
[M-28] +· (C 2 H 4 ) nonspecific; abundant: cyclo hexenes,
ethyl esters, propyl ketones, propylsubstituted aromatics
(CO) aromatic O, quinones, lactones,
lactams, unsaturated cyclic ketones,
allyl aldehydes
(N 2 ) diazo compounds; air (inten sity 3.7
times larger than for O 2
+· , m/z 32)
29
C 2 H 5
+ , CHO + [M-29] + (C 2 H 5 ) nonspecific; abundant: ethyl
(CHO) phenols, furans, aldehydes
30
CH 2 O +· ,
CH 2 NH 2
+ ,
NO + , C 2 H 6
+· ,
BF +· , N 2 H 2
+·
[M-30] +· (C 2 H 6 )
(CH 2 O)
(NO)
ethylalkanes, polymethyl compounds
cyclic ethers, lactones, primary
alcohols
nitro and nitroso compounds
N indicator
31
CH 3 O + ,
CH 3 NH 2
+· ,
CF + , N 2 H 3
+
[M-31] + (CH 3 O)
(CH 3 NH 2 )
(N 2 H 3 )
methyl esters, methyl ethers, primary
alcohols
O indicator
N-methylamines
hydrazides
32
O 2
+· ,
CH 3 OH +· ,
N 2 H 4
+· , S +·
[M-32] +·
(O 2 )
(CH 3 OH)
(S)
cyclic peroxides; air (intensity 3.7
times smaller than for N 2
+· , m/z 28)
methyl esters, methyl ethers
O indicator
sulfides (with 34 S isotope signal)