Understanding a Mass Spectrometer: How It Works, What It Measures, and Why It Matters
A mass spectrometer is a highly advanced analytical instrument used to identify, separate, and quantify molecules based on their mass-to-charge ratio (m/z). It is one of the most precise tools in modern science and is widely used in chemistry, biology, medicine, environmental testing, forensics, and pharmaceuticals.
Mass spectrometry (MS) allows scientists to detect even tiny amounts of substances, making it essential for everything from drug testing to cancer biomarker research.
What Is a Mass Spectrometer?
A mass spectrometer is a device that analyzes molecules by turning them into ions (charged particles) and measuring their masses.
It generates a mass spectrum — a graph showing the different molecules present in a sample and their quantities. This acts like a molecular fingerprint, helping identify unknown substances with high accuracy.
How a Mass Spectrometer Works
Mass spectrometry involves three main steps:
1. Ionization
The sample (liquid, gas, or solid) is converted into ions using an ion source.
Different ionization techniques include:
ESI (Electrospray Ionization) – for proteins, peptides, drugs
MALDI (Matrix-Assisted Laser Desorption/Ionization) – for biomolecules, polymers
EI (Electron Ionization) – for gases and volatile compounds