A device for enrichment sampling and ionization of volatile organic compounds in liquid samples

Abstract

The invention relates to a mass spectrometry instrument, in particular to an enrichment sampling and ionization device for volatile organic compounds in a liquid sample, comprising: a Venturi tube, a membrane enrichment sampling tube and an atmospheric pressure ionization source. The venturi tube includes a gas transmission tube, a constriction tube, a throat tube and an expansion tube arranged coaxially in sequence; the inlet end of the gas transmission tube is connected to an external high-pressure carrier gas source; the membrane enrichment sampling tube is a tubular membrane, and the membrane enrichment The sampling tube passes through the inside of the liquid sampling tube; a through hole is opened on the outer wall of the throat of the Venturi tube, and the outlet end of the membrane enrichment sampling tube is airtightly connected with the through hole; a mass spectrometer sampling Skimmer electrode is arranged on the expansion At the rear end of the tube outlet, the ionization region of the atmospheric pressure ionization source is set in the region between the Venturi tube and the mass spectrometry sampling Skimmer electrode. The invention adopts tubular membrane enrichment, Venturi sampling, and atmospheric pressure soft ionization technologies, and can realize high-throughput, rapid, and online detection of VOCs in liquid samples without sample pretreatment.

Description

technical field [0001] The invention relates to a mass spectrometer analysis instrument, in particular to a sampling and ionization device for a mass spectrometer, in particular to an enrichment sampling and ionization device for volatile organic compounds in a liquid sample. Background technique [0002] With the continuous acceleration of urbanization and industrialization, the water environment on which human beings rely is facing increasingly serious pollution problems. Volatile organic compounds (VOCs) are a class of organic compounds with a saturated vapor pressure greater than 133.322Pa at room temperature and a boiling point between 50°C and 260°C. Under normal circumstances, VOCs exist in the water environment at trace or trace levels, but most of them are toxic and irritating, and some even produce biological toxicity such as carcinogenicity and teratogenicity, causing serious damage to human health. Therefore, for the detection of a large number of samples in env...

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Problems solved by technology

However, mass spectrometry needs to work in a high-vacuum environment, and it is difficult for liquid samples to enter the mass spectrometer chamber directly for ionization and analysis. Usually, it is necessary to use headspace, extraction, etc. to extract the VOCs to be measured in the liquid sample, and then perform ionization and detection. However, this pretreatment method takes a long time; electrospray ionization can directly ionize the analyte in the liquid sample, and form gas-phase ions through desolvation to enter the mass spectrometer for analysis, but it is limited by the analyte in the liquid sample. The concentration of the measured substance, the detection sensitivity of direct electrospray ionization to trace VOCs in liquid samples is not high

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