Iontophoresis method of discontinuous atmospheric pressure interface

Abstract

The invention discloses an iontophoresis method for a discontinuous atmospheric pressure interface, and the method is characterized in that the method comprises the following steps: discontinuously transmitting ions under atmospheric pressure to a capturing device with reduced pressure intensity for multiple times by opening and closing a valve connected with the atmospheric pressure interface for two or more times; opening the valve, transmitting ions which are basically at atmospheric pressure into the capturing device, and capturing and gathering the ions, wherein closing the valve prevents the ions substantially at atmospheric pressure from continuing to transmit to the capture device. According to the method disclosed by the invention, the valve is discontinuously opened and closed for multiple times, and the capturing device is kept working to capture the ions during the period, so that the purpose of enriching the ions in the capturing device can be achieved, the ion introduction efficiency is greatly improved, and the sensitivity and the ion detection limit of the DAPI structure miniature mass spectrometer are improved.

Description

technical field [0001] The invention relates to the technical field of mass spectrometry, and more specifically refers to the improvement of a discontinuous atmospheric pressure interface iontophoresis method in a mass spectrometer. Background technique [0002] Micro-mass spectrometers are widely used in some on-site real-time analysis scenarios. Typical application scenarios include industrial wastewater monitoring, chemical warfare agent detection, pesticide and veterinary drug residue detection in food, and clinical diagnosis. [0003] The atmospheric pressure interface (API) of the mass spectrometer is used to transport ions from the normal pressure (atmospheric pressure) region to the low pressure region of the vacuum manifold. The application of API makes micro-mass spectrometers have unique advantages compared with laboratory mass spectrometers in field application scenarios, because API allows mass spectrometers to use a variety of ion sources working at atmospheric...

AI Technical Summary

Problems solved by technology

However, the iontophoresis time of a small mass spectrometer with a DAPI structure cannot be extended arbitrarily

Because once the pinch valve is opened to introduce ions, the air pressure in the vacuum chamber will rise rapidly. In order to maintain the minimum air pressure required by the ion trap plasma capture device in the ion cooling stage and the minimum air pressure required to maintain the normal operation of the turbomolecular pump, the pinch tube The opening time of the valve cannot be extended indefinitely, resulting in a limited number of ions entering the mass analyzer during the opening phase of the valve, which further limits the sensitivity and detection limit of the small mass spectrometer with DAPI structure

In addition, after the pinch valve is opened, ions will enter the vacuum chamber with high-speed airflow, which will negatively affect the mass stability of mass analysis and the stability of ion peak intensity (Huo X, Zhu X, Tang F, Zhang J, Zhang X, Yu Q, et al. Discontinuous Subatmospheric Pressure Interface Reduces the Gas Flow Effects on MiniatureCAPI Mass Spectrometer. Analytical Chemistry. 2020;92(5):3707-15.)

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