Final answer:
The molecular mass observed for Man9(GlcNAc)2 in a three-charge state is 3318.5 Da, which is determined by dividing the observed mass in mass spectrometry (9955.5 Da) by the charge state (+3).
Step-by-step explanation:
The molecular mass observed for Man9(GlcNAc)2 with a three-charge state ionization in mass spectrometry can be calculated using the observed mass (ESI-MS) divided by the charge state. Given the observed mass (ESI-MS) for a single charged molecule is 9955.5 Da, we divide this by the charge state of +3 to obtain the mass for each ion in the three charge states.
The calculation would be: 9955.5 Da / +3 = 3318.5 Da per charge state (ion).