Key fragment ions


Mass
Number	Key	Probable 	Additional Mass 
(m/e)	fragments	Parent Molecule(s)	Number (m/e)	
				
1	H+	H2	2	
	H+	H2O	18, 17, 16	
	H+	CxHy	12, 13, 14, 26, 27 etc.	
2	H2+	H2	1	
	He++	He	4	
4	He+	He	2	
6	C++	CO	12, 28, 29	
	C++	CO2	12, 28, 44	
	C++	CxHy	12, 13, 14, 26, 27 etc.	
7	N++	N2	14, 28, 29	
8	O++	O2	16, 32, 34	
	O++	H2O	16, 17, 18	
12	C+	CO	28, 29	
	C+	CO2	28, 29, 44	
	C+	CxHy	13, 14, 26, 27 etc.	
13	CH+	CxHy	12, 14, 26, 27 etc.	
14	N+	N2	28, 29	
	N+	NH3	15, 16, 17	
	CH2+	CxHy	12, 13, 26, 27 etc.	
	CO++	CO	28, 29	
15	CH3+	CxHy	12, 13, 14, 26, 27 etc.	
	NH+	NH3	14, 16, 17	
16	O+	O2	32, 34	
	O+	H2O	17, 18	
	CH4+	CH4	12, 13, 14, 15	
	NH2+	NH3	14, 15, 17	
17	OH+	H2O	16, 18	
	NH3+	NH3	14, 15, 16	
18	H2O+	H2O	16, 17	
19 	F+	F2	38	
	F+	HF	20	
20	HF+	HF	19	
	20Ne+	20Ne	22	
	Ar++	Ar	40	
22	CO2++	CO2	6, 12, 28, 29, 44	
	22Ne+	22Ne	20	
24	C2+	CxHy	12, 13, 14, 26, 27	
26	C2H2+	CxHy	12, 13, 14, 24, 27	
27	C2H3+	CxHy	12, 13, 14, 24, 26	
28	N2+	N2	7, 14, 29	
	C2H4+	CxHy	12, 13, 14, 24, 26	
	CO+	CO	6, 12, 29	
	CO+	CO2	6, 12, 29, 44	
29	C2H5+	CxHy	12, 13, 14, 24, 26, 27, 28	
	14N15N+	N2	7, 14, 28	
30	C2H6+	C2H6	12, 13, 14, 24, 26, 27, 28, 29	
	NO+	NO	14, 16	
31	C2H2OH+	C2H3OH	26, 28, 29 	
32	O2+	O2	8, 16, 34	
	S+	H2S	33, 34	
	S+	SO2	34, 64	
34	H232S+	H2S	32, 33	
	34S +	H2S	32, 33, 34	
	16O18O+	O2	8, 16, 32	
35	35Cl+	Cl2	37, 70, 72,74	
	35Cl+	HCL	36, 37, 38	
36	H35Cl+	HCl	35, 37, 38	
	36Ar+	Ar	20, 38, 40	
37	37Cl+	Cl2	35, 70, 72, 74	
	37Cl+	HCl	35, 36, 38	
38	H37Cl+	HCl	35,36,37	
	C3H2+	CxHy	12, 13, 14, 24, 26, 27, 28	
	38Ar+	Ar	20, 36, 40	
39	C3H3+	CxHy	12, 13, 14, 24, 26, 27, 28, 38	
	39K+	K	41	
40	Ar+	Ar	36, 38	
	C3H4+	CxHy	12, 13, 14, 24, 26, 27, 28, 38, 39	
41	C3H5+	CxHy	12, 13, 14, 24, 26, 27, 28, 38, 39	
	41K+	K	39	
42	C3H6+	CxHy	12, 13, 14, 24, 26, 27, 28, 38, 39	
43	C3H7+	CxHy	12, 13, 14, 24, 26, 27, 28, 38, 39	
	C2H3O+	C2H5OH (alcohol)	31, 44, 45, 46	
44	C3H8+	C3H8	41, 42, 43	
	CO2+	CO2	6, 12, 28, 29	
	C2H4OH+	C2H5OH (alcohol)	31, 43, 45, 46	
	N2O+	N2O	14, 16, 28	
45	C2H5O+	C2H5OH (alcohol)	31, 43, 44, 46	
	13CO2+	CO2	6, 12, 28, 29, 44	
46	NO2+	NO2	14, 16	
	C2H5OH+	C2H5OH (alcohol)	31, 43, 44, 45	
48	SO+	SO2	32, 64	
55	C4H7+	CxHy	12, 13, 14, 24, 26, 27, 28, 38, 39	
57	C4H9+	CxHy	12, 13, 14, 24, 26, 27, 28, 38, 39	
58	(CH3)2CO+	C3H6O (acetone)	43	
64	SO2+	SO2	32, 48	
77	C6H5+	Phenyl	50, 51, 52	
78	C6H6+	C6H6 (benzene)	50, 51, 52	
92.5	185Re++	Rhenium (filament)	93.5, 185, 187	
93.5	187Re++	Rhenium (filament)	92.5, 185, 187	
149		Phthalic ester (softening agent)		
182	182W+	Tungsten (filament)	183, 184, 186	
183	183W+	Tungsten (filament)	182, 184, 186	
184	184W+	Tungsten (filament)	182, 183, 186	
185	185Re+	Rhenium (filament)	187	
187	187Re+	Rhenium (filament)	185