Identify the base peak and the molecular peak of the following mass spectrum. What is the molar mass of the substance?
$\frac{m}{z}$ $=$ $29$ $\Rightarrow $ Base peak $\frac{m}{z}$ $=$ $30$ $\Rightarrow $ Molecular peak $ M$ $=$ $32 \frac{g}{mol}$
What causes the peak $\frac{m}{z}=31$ ?
This peak is probably due to the isotope $^{13}C$ present in the substance.
With $\frac{m}{z}$ $=$ $30$ can this be ethane?
No, the methylium peak at $\frac{m}{z}=15$ is missing!
Identify other fragments!
$\frac{m}{z}$ $=12$ $ \Rightarrow $ $C^+$ $\frac{m}{z}$ $=13$ $ \Rightarrow $ $CH^+$ $\frac{m}{z}$ $=$ $16$ $ \Rightarrow$ $O^+$
Do you see a specific peak?
The base peak $\frac{m}{z}$ $=$ $29$ could be due to the ion $CHO^+$
What substance is this?
Probably methanal $CH_2O$