| 0.984016 | OH ↔ NH2, e.g. de-amidiation, CHNO compounds |
| 1.99566322 | F ↔ OH, halogen exchange with hydroxy group (typically -F + OH) |
| 2.01565 | ± 2H, opening or forming of double bond |
| 4.955395 | Na+↔ NH4+, salt adduct |
| 7.00467078 | F ↔ CN, halogen exchange with cyano group |
| 8.96577868 | Cl ↔ CN, halogen exchange with cyano group |
| 13.979265 | O ↔ 2H, e.g. Oxidation followed by H2O elimination |
| 14.01565 | ± CH2, alkane chains, waxes, fatty acids, methylation |
| 14.01565 | -[C3H6ON] ↔ -[C2H4ON], acrylamide vs iodoacetamide in cysteine alkylation (gels) |
| 15.973937 | Na+↔ K+, salt adduct |
| 15.977156 | S ↔ O, sulfur compounds |
| 15.994915 | ± O, e.g. oxidation/reduction |
| 17.026549 | ± NH3, ammonium adduct/neutral ammonium loss |
| 17.026549 | NH4+ ↔ H+, salt adduct |
| 17.96611268 | Cl ↔ OH, halogen exchange with hydroxy group |
| 17.99057822 | F ↔ H, halogen exchange |
| 18.010565 | ± H2O, water addition/loss |
| 18.994581 | CN ↔ COOH, nitrile compounds |
| 20.929332 | K+↔ NH4+, salt adduct |
| 21.981944 | Na+↔ H+, salt adduct |
| 24.995249 | CN ↔ H, nitrile compounds |
| 27.010899 | ± HCN, nitrile compounds |
| 27.994915 | ± CO |
| 28.006148 | - 2N, nitrogen loss, e.g. azido compounds (N2) |
| 28.0313 | ± C2H4, natural alkane chains such as fatty acids |
| 29.97418 | NO2 ↔ NH2, nitro compounds |
| 29.997989 | -NO, nitroso compounds |
| 31.972071 | ± S, sulfur compounds |
| 31.98983 | ± 2O, oxygen loss |
| 33.021464 | - NH2OH, loss from hydroxamic acids |
| 33.96102768 | Cl ↔ H, halogen exchange |
| 33.987721 | ± H2S, sulfur compounds |
| 37.955881 | K+↔ H+, salt adduct |
| 37.989162 | 2CN ↔ 2COOH, nitrile compounds |
| 40.0313 | +(C3H6O - H2O), acetone condensation after dehydration |
| 42.010565 | ± COCH2 |
| 42.04695 | ± C3H6, propylation |
| 43.005814 | ± CONH (wrong calc. in ref.) |
| 43.94948442 | 79Br ↔ Cl, halogen exchange |
| 43.98983 | ± CO2 |
| 45.94743792 | 81Br ↔ Cl, halogen exchange |
| 47.966986 | ± SO, sulfur compounds |
| 52.9152631 | 79Br ↔ CN, halogen exchange with cyano group |
| 54.9132166 | 81Br ↔ CN, halogen exchange with cyano group |
| 56.0626 | ± C4H8, butylation |
| 58.00548 | ± CO2CH2 |
| 58.041865 | +C3H6O, acetone condensation |
| 61.9155971 | 79Br ↔ OH, halogen exchange with hydroxy group |
| 63.9135506 | 81Br ↔ OH, halogen exchange with hydroxy group |
| 63.961901 | ± SO2, sulfur compounds |
| 63.998286 | -CH3SOH, loss from oxidized methionine residues |
| 77.9105121 | 79Br ↔ H, halogen exchange |
| 79.9084656 | 81Br ↔ H, halogen exchange |
| 79.956816 | ± SO3, sulfur compounds |
| 91.93562072 | I ↔ Cl, halogen exchange |
| 97.967381 | ± H2SO4, sulfur compounds |
| 97.976897 | ± H3PO4, phosphorous compounds |
| 100.9013994 | I ↔ CN, halogen exchange with cyano group |
| 109.9017334 | I ↔ OH, halogen exchange with hydroxy group |
| 125.8966484 | I ↔ H, halogen exchange |
| 146.05791 | ± [Deoxy-Hexose-H2O, C6O4H10], e.g. Fucose |
| 162.052825 | ± [Hexose-H2O, C6O5H10], e.g. Glucose, Galactose, Mannose, Fructose |
| 164.068475 | ± [Deoxy-Hexose-H2O, C6O5H12], e.g. Fucose |
| 176.03209 | ± [Glucuronic acid-H2O, C6O6H8] |
| 180.06339 | ± [Hexose, C6O6H12], e.g. Glucose, Galactose, Mannose, Fructose |
| 194.042655 | ± [Glucuronic acid, C6O7H10] |
| 203.079374 | ± [HexNAc-H2O, C8O5NH13], N-acetylhexoseamine |
| 206.05791 | + sinapic acid - H2O, MALDI-matrix adduct |
| 221.089939 | ± [HexNAc, C8O6NH15], N-acetylhexoseamine |
| 289.073243 | ± [Glutathione-H2O, C10O5N3SH15] |
| 291.095419 | ± [Neu5Ac-H2O, C11O8NH17], sialic acid |
| 305.068158 | ± [Glutathione+O-H2O, C10O6N3SH15] |
| 307.083808 | ± [Glutathione, C10O6N3SH17] |
| 309.105984 | ± [Neu5Ac, C11O9NH19], sialic acid |
| 324.10565 | ± [Sucrose-H2O, C12O10H20] |
| 342.116215 | ± [Sucrose, C12O11H22] |
| 484.171011 | +Tetraphenyl-tetramethyl-trisiloxane (silicone-based oil) |
| 546.186661 | +Pentaphenyl-trimethyl-trisiloxane (silicone-based oil) |