What Is Mass Spectrometry? An Introductory Guide

Imagine you’re presented with an unknown chemical substance and tasked with finding out what it is. You might look at it under a magnifying glass or microscope, examine how it interacts with other known chemicals, or take note of its physical properties. These basic tests can help you get a general idea of what it might be, but you won’t be able to come up with any exact answers.

When real-life scientists are in this situation, they often use a technique called mass spectrometry to test the material. This method can identify exactly what something is made of down to a particle level.

What is mass spectrometry, how does it work, and how does it get used in practice? Keep reading to find out.

What Is Mass Spectrometry?

A mass spectrometer machine (also called a mass spec) converts samples into charged particles called ions. Once they’re converted, the machine uses electric and magnetic fields to sort these ions by their charge and mass. In essence, it organizes them in a spectrum by mass (hence the name “mass spectrometry”).

Scientists can then compare the spectrum they get from their sample to the spectra of known substances. This helps them identify both the composition and molecular structure of unknown chemical substances.

How Does a Mass Spectrometer Work?

A mass spectrometer can test solid, liquid, and gas samples. Each phase of matter takes different preparation, but the testing always follows the same five steps.

  1. Vaporization: First, the sample gets injected into the ionizing tube. If it isn’t already in the gas phase, it’s heated up until it vaporizes and can keep moving through the machine.
  2. Ionization: Next, an electron gun shoots charged particles at the sample until the whole thing has a positive charge. This makes the substance attracted to magnetic fields.
  3. Acceleration: The machine shoots the positive sample at high speeds through negatively-charged plates. Because opposite charges attract, the positively-charged sample sticks to the plates.
  4. Separation: The machine keeps moving the sample ions through the magnetic field. As they pass through, the ions spread out in a gradient from highest to lowest mass based on how attracted they are to the negative plates.
  5. Detection: At the end of the mass spec is a detector. When ions pass through, it records the electric current and the part of the plate each ion hits. Particles of a certain type will always hit the same place on the plate.

The final data a mass spec gives you is called the mass-to-charge ratio. You can also plug this data into an equation to find the exact molecular weight of each component in a sample.

How Do Scientists Use a Mass Spectrometer?

Mass spectrometers have countless scientific uses. Microbiologists use it to perform microbial typing in tests like the MALDI-TOF ID protocol. If you’re curious about how it works, you can visit their site to take a look at how it identifies different probiotics and bacteria.

Aside from microbiology, other uses for mass spectrometry include:

  • medical and criminal forensics
  • isotope dating
  • proteomics
  • metabolomics
  • lipidomics
  • trace gas analysis
  • pharmaceutical development

If there’s a lab that does chemistry, biology, or physics research, there’s a good chance they use mass spectrometry.

Keep Learning About Fascinating Scientific Innovations

Mass spectrometry has a place in every branch of physical and natural science. It makes analyzing chemical substances possible for medical labs, biological research, and even forensic investigations.

Even so, mass spectrometry is only one of the many ways to identify the composition of an unknown substance. If you want to learn more about the tools scientists rely on every day, keep reading through the rest of our site.

Recommended For You

About the Author: Jacob Wyatt