| Protecting group | Mass Change |
| Methyl | 14.027 (Me) |
| Formyl | 28.104 (CHO) |
| Ethyl | 28.054 (Et) |
| Acetyl | 42.037 (Ac) |
| t-Butyl | 56.108 (t-Bu) |
| Anisyl | 90.126 |
| Benzyl | 90.126 (Bzl) |
| Trifluroacetyl | 96.009 (Tfa) |
| N-hydroxysuccinimide | 97.073 (ONSu, OSu) |
| t-Butyloxycarbonyl | 100.117 (Boc) |
| Benzoyl | 104.108 (Bz) |
| 4-Methylbenzyl | 104.152 (Meb) |
| Thioanizyl | 106.191 |
| Thiocresyl | 106.191 |
| Benzyloxymethyl | 120.151 (Bom) |
| 4-Nitrophenyl | 121.095 (ONp) |
| Benzyloxycarbonyl | 134.134 (Z) |
| 2-Nitrobenzoyl | 149.106 (NBz) |
| 2-Nitrophenylsulphenyl | 153.161 (Nps) |
| 4-Toluenesulphonyl | 154.189 (Tosyl,Tos) |
| Pentafluorophenyl | 166.050 (Pfp) |
| Diphenylmethyl (Dpm) | 166.222 (Dpm) |
| 2-Chlorobenzyloxycarbonyl | 168.579 (Cl-Z) |
| 2,4,5-trichlorophenyl | 179.432 |
| 2-bromobenzyloxycarbonyl | 213.031 (Br-Z) |
| 9-Fluorenylmethyloxycarbonyl | 222.243 (Fmoc) |
| Tripheylmethyl | 242.320 (Trityl, Trt) |
| 2,2,5,7,8-pentamethyl-chroman-6-sulphonyl | 266.361 (Pmc) |
The masses of commonly occuring protecting groups used in solid phase synthesis. The masses quoted are the average mass change in a peptide when one of these groups is present.