A-Level Chemistry Mass Spectra help

I was looking at this example in my textbook and saw that there is a small peak at the end for an m/z of 59 and 60 for both propanal and propanone? How did this arise if the relative molecular mass of both molecules are 58?

I was looking at this example in my textbook and saw that there is a small peak at the end for an m/z of 59 and 60 for both propanal and propanone? How did this arise if the relative molecular mass of both molecules are 58?

The presence of hydrogen isotopes and other isotopes.

Probably due to carbon 13 and other O isotopes rather than H isotopes.

Probably due to carbon 13 and other O isotopes rather than H isotopes.

On consideration, I see that you are quite right. Carbon 13 makes up over 1% of naturally occurring carbon, while deuterium is only about 0.02%.

My first thought was that as there are many hydrogen atoms in the structures the deuterium would also be significant, but even with butane this only has a minor contribution compared to 13C.

Thanks for the correction.