Because of the superior role in differentiating similar amino acids and many kinds of modifications, mass spectrometry is widely used in the biopharmaceutical industry for accurate molecular weight determination. Two approaches, MALDI-TOF and ESI-TOF, are available at Creative Proteomics to determination of the molecular weights of intact proteins. amino acid molecular weight https://www.creative-proteomics.com/pronalyse/molecular-weight-determination-intact-mass.html