Matrix-assisted laser desorption ionization time-of-flight mass spectrometer and sample detection method

Abstract

The invention discloses a matrix-assisted laser desorption ionization time-of-flight mass spectrometer and a sample detection method. The mass spectrometer comprises a sealed shell for forming a vacuum cavity, a laser positioned outside the sealed shell, a target plate contained in the sealed shell, a modulation electrode set, a first deflection electrode set, a first reflecting mirror, a flight tube and a detector, wherein the laser is used for emitting laser beams to the sealed shell; the first reflecting mirror is used for reflecting the laser beams to enable the laser beams to vertically irradiate a sample placed on the target plate; the modulation electrode set is used for modulating ion beams emitted by gasification and ionization of the sample under the vertical irradiation of the laser beams, and the ion beams contain effective ions, neutral particles and non-selective ions; and the first deflection electrode set is used for generating a first electric field to deflect a flight direction of the effective ions in the modulated ion beams, so that the effective ions subjected to flight direction deflection enter one end of the flight tube in the axial direction of the flight tube and are received by the detector arranged at the other end of the flight tube.

Description

technical field [0001] The invention relates to the technical field of instruments and meters. More specifically, it relates to a matrix-assisted laser desorption ionization time-of-flight mass spectrometer and a sample detection method. Background technique [0002] A mass spectrometer is an instrument that uses electronic measurement technology to measure the mass-to-charge ratio (m / z) value and its intensity of ions. It uses the sample introduction system to introduce the sample to be tested into the mass spectrometer, uses the ion source to ionize it, and the mass analyzer separates the ions according to their mass-charge ratio by applying an electric field, and uses the detector to separate the ion signals according to their mass-charge ratio. Rate and record the intensity. In addition to fast atom bombardment mass spectrometry (FAB), atmospheric pressure chemical ionization mass spectrometry (APCI), and electrospray ionization mass spectrometry (ESI), matrix-assisted...

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Problems solved by technology

[0005] On the one hand, due to the incident mode of the laser beam, the laser beam irradiating the sample forms an acute angle with the bearing surface of the target plate, which will lead to a low degree of ionization of the sample and divergence of the flight initial angles of most of the formed ions, resulting in a high utilization rate of the sample. Low and the detection sensitivity of the mass spectrometer is low

On the other hand, bulk desorption will also occur during the ionization process of matrix molecules absorbing energy from the laser beam, which will cause the detector to receive a large number of useless neutral particles and non-selective ions, shortening the life of the detector , and neutral particles and non-selective ions will interfere with the detection of the sample, reducing the signal-to-noise ratio of the mass spectrometer detection signal

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