By feeding the entire mixture into the mass spectrometer, the researchers can quickly spot a peptide produced by a mutant.

ECONOMIST: Viruses

These samples were run through a mass spectrometer - a device that effectively measures all the masses of the chemical compounds in the breath.

BBC: Exhaled breath is unique fingerprint

As more drops are sprayed on the same spot, some of this film is scattered and sucked into a mass spectrometer, which can identify the molecules collected.

ECONOMIST: Forensic technology

Three tests, including one that used a highly sensitive mass spectrometer, indicated the presence of the nerve agent cyclosarin and an unspecified blister agent in a stash of 55-gallon drums, the officer said.

CNN: Initial tests of Iraqi chemicals show nerve agent

Only when Centers for Disease Control and Prevention scientists sent a suspect sample to the mass spectrometer did they discover the new variety of swine flu, according to an article describing the techniques in Science magazine.

CNN: Commentary: Flu shouldn't close Mexico border

To measure this, archaeologists use a device called an accelerator mass-spectrometer.

ECONOMIST: Monitor

AIDS. The likelihood that a mutant protein can slip through unnoticed is small: the spectrometer can tell apart proteins that differ by less than a tenth of a proton mass in weight.

ECONOMIST: Viruses: Hunt the mutant | The