Instrumental analysis

Mass Spec. paper

1. Describe completely how the authors experimental set up works. You may need to read other

references cited in the paper. Be sure to discuss why the nano-LC system is used, why the FI-

ICR is used, and why fragmentation of the protein is done. Draw diagrams as appropriate

2. Assuming the average number of charges per protein in the lysised cell is 50, how many

proteins are being scanned by the ICR MS for a given scan? What is this in moles of protein?

What is the signal to noise for a single scan?

3. From an analytical point of view what is really cool about Table 1? B) Why do two of the

biomolecules in Table 1 only produce 5 fragments (Hint: think about their biological function)?

4. Assuming the number charges on the biomolecules in Table 1 varies from 40 to 60, what is

the range of frequencies that have to be scanned by the ICR. See equation 20-11 in your book.

5. A majority of the proteins have a relatively small error in mass for the protein of interest. If

the average charge on a protein in 50 in the MS, what is the error in frequency for a mass of

25000 and 48000 Daltons for a 20 ppm error in mass?

6. How were the authors able to see a 72000 Dalton protein given their limitation in the

frequencies they could scan?