Table 1.

Site-specific fragmentation of CXCL8 proteoform ions by top-down ion trap tandem mass spectrometry at limited fragmentation energy.

CXCL8 form	Selected precursor ion for fragmentation [m/z value (z)]	Signature fragment ions [m/z value (z)]	Corresponding amino acids in the sequence of CXCL8
CXCL8(-2-77)	911.5 [10+]	615.3 [4+] 1105.8 [6+]	58-77 −2-57
CXCL8(1-77)	892.8 [10+]	615.3 [4+] 1077.7 [6+]	58-77 1-57
CXCL8(2-77)	885.7 [10+]	615.3 [4+] 1065.9 [6+]	58-77 2-57
CXCL8(3-77)	875.8 [10+]	615.3 [4+] 1049.3 [6+]	58-77 3-57
CXCL8(6-77)	932.3 [9+]	615.3 [4+] 1185.7 [5+]	58-77 6-57
CXCL8(7-77)	922.6 [9+]	615.3 [4+] 1168.3 [5+]	58-77 7-57
CXCL8(8-77)	914.6 [9+]	615.3 [4+] 1154.0 [5+]	58-77 8-57
CXCL8(9-77)	900.4 [9+]	615.3 [4+] 1128.7 [5+]	58-77 9-57