Question

A protein with molecular weight of 20000 Dalton contains five and four charges. A
what M/Z are protein ions detected by mass spectrometer?
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Answer 1

Answer:

In the mass spectrum, the heaviest ion (the one with the greatest m/z value) is likely to be the molecular ion. A few compounds have mass spectra which don't contain a molecular ion peak, because all the molecular ions break into fragments.

Answer 2

Given

• Molecular Weight of protein = 20,000 Dalton
• Charges = 5 and 4

Find

• m / z value to find the sequence of protein ions detected by the mass spectrometer

where,

• m= total mass of an ion a
• z= total charge
• Mr= average mass of the protein

Use

• m / z = M + nH / n

So,

• m / z = 20,005 / 5 = 4001
• m / z = 20,004 / 4 = 5001

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~ It detects protein ions at m/z= 4001 and 5001 respectively