Using the mass spectrum below, answer the following questions: m/z a. In Mass sp

Question

Using the mass spectrum below, answer the following questions:

m/z

a. In Mass spectrometry, what does m/z represent?

b. Describe which peak represents the base peak.

c. Describe which peak represents the molecular ion Relative Abundance (%)

d. Which peak is the M+ - 15 peak? What radical is typically lost to produce this?

e. Which peak is the M+ - 29 peak? What radical is typically lost to produce this?

f. Given that this spectrum is from ethyl methyl ketone, propose structures for the fragment ions at m/z 57 and 43.

Explanation / Answer

a).In mass spectrum m/z means , mass(m) divided by charge number(z). In otherwords m/z = mass to charge ratio.

b). The peak in the mass spectrum with the greatest intensity ( tallest peak) is called the base peak (due to the ion with the greatest relative abundance and assigned 100 % intensity). Here the tallest peak is at m/z = 43 and this is the base peak.

c).

In the mass spectrum, the heaviest ion (the one with the greatest m/z value) is likely to be the molecular ion. So here the peak at m/z 72 represents the molecular ion peak.

d). The peak at m/z 15 = CH3+. Here the radical lost is C2H5CO.

e) The peak at m/z 29 = CH2CH3+. The radical lost to produce is CH3CO.

f) The fragment ions at 57 = C2H5CO+ and the fragment ion at m/z 43 = CH3CO+

Related Questions

Navigate

• Browse (All)
• Browse U
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.