A kind of ion mobility spectrometer and its carrier gas flow control method

Abstract

The invention provides an ion mobility spectrometer and a method for controlling the flow rate of the carrier gas thereof. The ion mobility spectrometer includes a migration tube for completing ion migration, an ionization source for generating reagent ions, and a sample for transporting samples into the migration tube. Gas sampling device, molecular sieve for drying and purifying carrier gas, flow control unit, temperature control unit, humidity sensor unit and processor unit for measuring and controlling temperature, humidity and carrier gas flow. The present invention adjusts and controls the humidity of the carrier gas entering the transfer tube by setting a humidifying bottle and a flow valve, and sets a humidity sensor at the gas outlet of the transfer tube and the outlet of the molecular sieve to compare the humidity difference detected by the two to determine whether the molecular sieve is invalid ; The carrier gas flow is controlled by the expert-assisted PID control method, which improves the accuracy and stability of the carrier gas flow control; the invention adopts an embedded design, which is convenient to use and strong in flexibility, and is suitable for field application.

Description

technical field [0001] The invention relates to an ion mobility spectrometer and its temperature, humidity, and flow measurement and control technology, in particular to an ion mobility spectrometer and a method for controlling the flow of a carrier gas. Background technique [0002] Ion mobility spectrometry (IMS) technology is an analytical technique based on the difference in the migration rate of different gas phase ions or charged clusters in the electric field to characterize the species or form of the substance in the gas phase. The ion mobility spectrometer has high sensitivity and fast detection speed. , small size, low power consumption, and can work at atmospheric pressure and room temperature, etc., have been widely used in the rapid detection of explosives, drugs, chemical reagents and environmental pollutants. An ion mobility spectrometer generally includes a sampling device and an ion transfer tube as a core component. The ion transfer tube is mainly composed ...

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Problems solved by technology

[0004] At present, the small surface desorption atmospheric pressure chemical ion source ion mobility spectrometer (miniDAPCI-IMS) commonly used in the laboratory transmits the measured temperature, humidity and carrier gas flow parameters to the PC, and monitors and corrects each parameter on the PC. This method is suitable for laboratory application, but there are still the following disadvantages: although this method can realize humidity monitoring on the PC side, the humidity adjustment control mechanism is not set in the instrument, and indicators are used to identify the failure of molecular sieves, mainly relying on manual experience Judgment, inconvenient to use, and easy to misjudgment; the pressure sensor for carrier gas flow detection is installed in the circulating gas circuit, and the method of split flow is used for detection. Due to the large fluctuation of carrier gas flow, the error is large; Portable, not suitable for field applications

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