Directly-heated type tubular film enriching and sampling device used for online mass spectrum

Abstract

The invention relates to a directly-heated type tubular film enriching and sampling device used for online mass spectrum. The directly-heated type tubular film enriching and sampling device comprises a tubular film, heating wires, a film sampling cavity, a carrier gas, a sampling metal tube and an emergency switching-off solenoid valve. The tubular film is a pore-free compact polydimethylsiloxane tubular film. In the device, the tubular film is adopted to sample and quickly enrich the samples; heating wires are uniformly wound outside the film as a film heating device; a cavity outside the film is connected with mass spectrum by a metal capillary tube to form a negative-pressure state; a gas carrying device is additionally arranged outside the film. When the tubular film is under action of stretching, heating, pressure difference and carrier gas, samples can be quickly enriched through the tubular film. Penetration rate and penetration velocity of samples in the film sampling device are improved.

Description

technical field [0001] The invention belongs to a mass spectrometry analysis instrument, in particular to a direct-heating tubular membrane enrichment and sampling device for on-line mass spectrometry. The device can realize online enrichment of volatile organic pollutants in liquid samples and gas samples. Under the action of stretching, pressure difference, heating and carrier gas, the analytical sample quickly passes through the membrane and is enriched in the cavity outside the membrane, and is brought into the ionization region of the mass spectrometer by the carrier gas for ionization. The transmission rate and transmission rate of the sample in the membrane sampling device are improved. Background technique [0002] Although the concentration of volatile and semi-volatile organic pollutants in water and air is low, most of them have pathogenic, teratogenic and carcinogenic effects. Therefore, the online detection of organic pollutants in the environment has been wid...

AI Technical Summary

Problems solved by technology

At the same time, due to the selective permeability of the semi-permeable membrane, it is difficult for inorganic substances such as nitrogen and oxygen in water and air to permeate the membrane, while volatile and semi-volatile organic substances are easily enriched through the membrane.

However, in order to meet the vacuum requirements of the mass spectrometer, the common sheet-shaped membrane sampling device makes the membrane area small, and the membrane is very thin and easy to break

Small membrane area and less contact with samples, resulting in lower membrane enrichment efficiency

Although the ordinary tubular membrane has a large specific surface area, the large thickness of the membrane wall makes the sample transmission rate low, the enrichment efficiency is low, the transmission speed is slow, and the response time of the membrane is long, so it is not suitable as a rapid detection method.

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