The principle of mass spectrometer is to bombard sample molecules with high-energy electron current, so that the molecules lose electrons and become positively charged molecular ions and fragment ions. These different ions have different masses, and the time for them to reach the detector under the action of magnetic field is also different. The result is mass spectrometry.

The core of mass spectrometer is ion source, mass analyzer and ion detector. Ion source is a device that ionizes sample molecules under high vacuum. Ionized molecules will be further split into various fragment ions and neutral particles with smaller mass because they receive too much energy. They get the average kinetic energy of the same energy under the action of accelerating electric field and enter the mass analyzer. The mass analyzer is a device to separate ions of different masses that enter it at the same time according to the mass-to-charge ratio m/e.

The separated ions enter the ion detector in turn, and the amplified ion signals are collected, processed by computer and drawn into mass spectra. There are various types of ion sources, mass analyzers and ion detectors. Mass spectrometer can be divided into isotope mass spectrometer, inorganic mass spectrometer and organic mass spectrometer according to the application scope; According to the resolution, it can be divided into high resolution, medium resolution and low resolution mass spectrometer; According to the working principle, it can be divided into static instrument and dynamic instrument.

Extended data

Organic mass spectrometer is mainly used for structural identification of organic compounds, which can provide structural information such as molecular weight, elemental composition and functional groups. Divided into quadrupole mass spectrometer, ion trap mass spectrometer, time-of-flight mass spectrometer and magnetic mass spectrometer.

An important aspect of the development of organic mass spectrometer is the use of various combined instruments (gas chromatography, liquid chromatography, thermal analysis, etc.). Its basic working principle is to use an instrument with separation technology as the "sampler" of the mass spectrometer to separate the organic mixture into pure components and enter the mass spectrometer, thus giving full play to the analytical expertise of the mass spectrometer and providing molecular weight and molecular structure information of each component.

It can be widely used in organic chemistry, biology, geochemistry, nuclear industry, material science, environmental science, medical and health care, food chemistry, petrochemical industry and other fields, as well as special analysis aspects such as space technology and public security work.