Mass Spectrum and Different Peaks In Spectroscopy

Mass Spectrum and Different Peaks In Spectroscopy

A method for figuring out a sample’s molecular weight and makeup is mass spectrometry. The material is ionized, and the ions that arise are subsequently separated according to the mass-to-charge ratio. The resulting spectrum is known as a mass spectrum, and it offers crucial details regarding the make-up and structure of the sample.

A mass spectrum can have a number of different peak types, each of which corresponds to a different kind of ion. Several of the most typical peaks include:

Molecular ion peak (M+):

This peak represents the full-fledged molecule. It is the most significant peak in the spectrum and stands for the molecular weight of the sample.

Fragment ion peak (M+1, M+2, etc.):

These peaks represent ions that are created when a molecular ion fragments. They are helpful in figuring out the molecule’s structure.

Isotopic peak

An ion that comprises one or more isotopes of the same element is said to have an isotopic peak. Because different isotopes have somewhat different masses, they can form peaks at various mass-to-charge ratios.

Adduct peak:

This peak is associated with an ion that has formed an adduct with another molecule. Mass spectrometry frequently uses adducts, which can reveal details about the sample’s chemical environment.

Base peak:

With a relative abundance of 100%, this peak is the strongest in the spectrum. The percentage of the base peak is used to report all other peaks.


Along with mass spectrometry, other spectroscopy techniques such as nuclear magnetic resonance (NMR) spectroscopy and infrared spectroscopy can also create various sorts of peaks that reveal details about the structure and composition of a material.