Ion mobility spectrometer and carrier gas flow control method thereof

Abstract

The invention provides an ion mobility spectrometer and a carrier gas flow control method thereof. The ion mobility spectrometer comprises a migration tube used for completing ion migration, an ionization source used for generating reagent ions, a sample introduction device used for conveying a sample gas into the migration tube, a molecular sieve used for drying and purifying a carrier gas, and a flow control unit, a temperature control unit, a humidity sensing unit and a processor unit, which are used for measuring and controlling temperature, humidity and the carrier gas flow. According to the ion mobility spectrometer provided by the invention, a humidification bottle and a flow valve are arranged to adjust and control the humidity of the carrier gas in the migration tube, and humidity sensors are arranged at a gas outlet of the migration tube and an outlet end of the molecular sieve to compare a humidity difference detected by the two and judge whether the molecular sieve is ineffective or not; an expert assistance PID control method is used for controlling the carrier gas flow, in order to improve the control precision and stability of the carrier gas flow; and the ion mobility spectrometer provided by the invention adopts an embedded design, thereby being convenient to use, strong in flexibility and suitable for onsite 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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