ESI-MS for glycopeptides 16. Chemical formula: C486H791N131O161S2, calc. Mass: 11102.72, [M+6H]6+: 1851.45, [M+7H]7+: 1587.10, [M+8H]8+: 1388.84, [M+9H]9+: 1234.64, [M+10H]10+: 1111.27, [M+11H]11+: 1010.34, [M+12H]12+: 926.23; Observed mass: [M+6H]6+: 1852.31, [M+7H]7+: 1588.08, [M+8H]8+: 1389.84, [M+9H]9+: 1235.09, [M+10H]10+: 1111.95, [M+11H]11+: 1010.94, [M+12H]12+: 927.18