Question

Differenciate between base peak and molecular ion peak

Answer 1

In the mass spectrum, the heaviest ion (the one with the greatest m/z value) is likely to be the molecular ion.

Or In a mass spectrum, the peak representing the molecular ion is called the molecular ion peak (symbol: M peak). Excluding any peaks due to the presence of heavier isotopes, the molecular ion peak is the peak with the highest mass-to-charge ratio. And

Base peak: The most intense (tallest) peak in a mass spectrum, due to the ion with the greatest relative abundance (relative intensity; height of peak along the spectrum's y-axis). Not to be confused with molecular ion: base peaks are not always molecular ions, and molecular ions are not always base peaks.