Question

In mass spectroscopy, what does the M+1 peak indicate? a) Molecular ion (parent ion)

b) Fragmentation
c) Isotope distribution
d) Background noise

Answer 1

The M+1 peak in mass spectroscopy indicates isotope distribution, which occurs due to the presence of isotopes that are one mass unit higher than the most abundant isotope.

Step-by-step explanation:

In mass spectroscopy, the M+1 peak represents the isotope distribution within the sample being analyzed. This peak occurs due to the presence of naturally occurring isotopes that are one mass unit higher than the most abundant isotope, which contributes to the molecular ion peak (M peak). For example, the carbon isotope 13C contributes to the M+1 peak in organic compounds because it is one mass unit greater than the more common 12C isotope.

The M+1 peak therefore indicates c) Isotope distribution in a mass spectrum. It helps chemists understand the elements in the compound as well as the possible isotopic composition of those elements.