Ion mobility spectrometer with double-circulation gas circuits

Abstract

The invention discloses an ion mobility spectrometer with double-circulation gas circuits. The ion mobility spectrometer comprises a sample vaporizing chamber, a sample molecule collecting chamber, a diaphragm, a migration tube, an outer circulation activated carbon filter tip, an outer circulation pump, a sampling pump, a two-position three-way solenoid valve, an inner circulation doping unit, an inner circulation drying unit and an inner circulation pump. The sample vaporizing chamber and the sample molecule collecting chamber are communicated, and the diaphragm is arranged in the sample molecule collecting chamber. By the adoption of the ion mobility spectrometer with the double-circulation gas circuits, long-term dryness and cleanness of the ion mobility spectrometer in the operation process can be kept due to the arrangement of the inner circulation gas circuit and the outer circulation gas circuit, sampling detection is accurate, due to the arrangement that the ion mobility spectrometer can be closed completely when turned off, it can be effectively ensured that the ion mobility spectrometer can recover to the normal standby state for detection fast, and the problems that according to an ion mobility spectrometer in the prior art, due to the external atmosphere environment, detection sensitivity is reduced, and the probability of alarm missing and false alarms of the ion mobility spectrometer is greatly increased are avoided.

Description

technical field [0001] The invention relates to the technical field of ion migration, in particular to an ion mobility spectrometer with a double-circulation gas path. Background technique [0002] Ion mobility technology, as a kind of molecular detection technology, originated in the 1960s. The basic principle of ion mobility spectrometer is to measure the migration of characteristic ions in a weak electric field by sucking the measured molecules into the transfer tube and ionizing them. rate to detect the species of trace substances. Ion mobility spectrometers usually use radiation ionization sources to achieve ionization of molecules. This process is a chemical reaction process between molecules and ions in the gas phase. The concentration of ions directly affects the detection results. According to the definition of chemical reaction equilibrium constant, the concentration of characteristic product ions depends not only on the concentration of measured molecules, but a...

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Problems solved by technology

It is difficult for traditional ion mobility spectrometers to maintain a low concentration of polar small molecules inside the transfer tube during sampling and detection, and to keep the transfer tube clean and dry for a long time during standby operation and shutdown. In addition, traditional ion mobility The main problems of the spectrometer are as follows: first, the molecules of the substance to be measured tend to remain on the pipes and side walls of the sampling unit; second, the cooling of the thermal transfer tube after shutdown can easily lead to the contraction of the internal circulation gas, causing the external impurity molecules to enter and migrate inside the tube

Under the above circumstances, when the ion mobility spectrometer is under test, the ion spectrum is complex, and the ionization ability of the radioactive source is weakened, which will eventually lead to the decrease of the detection sensitivity of the ion mobility spectrometer, the leakage alarm of the ion mobility spectrometer, and the greatly increased probability of false alarms.

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