ESI positive	detected ions	Notes
[M+H]+	M+1	amines
[M+NH4]+	M+18
[M+Na]+	M+23
[M+K]+	M+39
[M+H+NEt3]+	M+102	in triethylammonium buffer
[M+H+CH3CN]+	M+42
[M+NH4+CH3CN]+	M+59
[M+Na+CH3CN]+	M+64	phenol origoethoxylates
[2M+H]+	2M+1
[2M+NH4]+	2M+18
[1/2M+NH4]+	1/2M+18	PEG analogs, approx. >1,000 MW compounds
[1/nM+NH4]+	1/nM+18	high MW PEG analogs
[2M+Na]+	2M+23
[M+2H]2+	M+2
[M+2Na]2+	M+46
[M]+	M	quaternary ammonium
[(1/n)M+Y]+	Y=(18n-17)/n (1≦n)	NH2-PEG-R　Y=(1+18×(n-1))/n 9.50(n=2)/12.33(3)/13.75(4)/14.60(5)/15.17(6)
[(1/n)M+Y]+	Y=(18n-34)/n (2≦n)	NH2-PEG-NH2　Y=(1+1+18×(n-2))/n 1.00(n=2)/6.67(3)/9.50(4)/11.20(5)/12.33(6)
ESI negative	detected ions	Notes
[M-H]-	M-1	carboxylic acid
[M+Cl]-	M+35,　M+37
[M+HCOO]-	M+45	in formic acid buffer
[M+CH3COO]-	M+59	in acetic acid buffer
[M+CF3COO]-	M+113	in TFA buffer
[2M-H]-	2M-1
[1/2M-H]-	1/2M-1
[2M+HCOO]-	2M+45	in formic acid buffer