Online enrichment and desorption device of particulate organic matters and application method thereof

Abstract

The invention relates to an online enrichment and desorption device of particulate organic matters and an application method thereof. The online enrichment and desorption device of particulate organicmatters comprises a thermal desorption unit, a high-temperature-resistant desorption unit, a capillary capture column, a semiconductor cold trap, an electronic tee valve, a gas chromatographic columnand other components. Particulate organic matters pass through the thermal desorption unit; the particulate organic matters are then captured successively by the capillary capture column of normal temperature and the semiconductor cold trap before emptying; the captured organic matters are reversely fed via valve switching; low-boiling-point components trapped by the semiconductor cold trap are released first by thermal desorption; high-boiling-point components trapped by the capillary capture column are heated with a gas chromatographic column heater program and are gradually desorbed beforeentering the gas chromatographic column for separation and detection. The emptying design helps increase thermal desorption flow, reduce thermal desorption time, improve thermal desorption efficiencyand prevents accumulative pollution of a chromatographic column and detection unit due to direct entry of the thermal desorption sample in the chromatographic column; the advantage that high-boiling-point components are trapped by capillaries of normal temperature and low-boiling-point components are trapped by the cold trap at low temperature is utilized such that the low-boiling-point and high-boiling-point organic matters are trapped stagewise; organic matter trapping and releasing efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of environmental monitoring, and in particular relates to an online enrichment and analysis device for particulate organic matter and a use method thereof. Background technique [0002] Organic matter in atmospheric particulate matter is one of its main components, and its content can account for 20%-80% of its total. The composition of organic matter in atmospheric particulate matter is quite complex, with a large concentration range and different physical and chemical properties, and dynamic chemical evolution occurs in the atmospheric environment all the time. Therefore, online measurement technology is of great significance for understanding the dynamic changes of organic matter in particulate matter in the atmospheric environment. The online measurement technology of the molecular composition of particulate organic matter is quite difficult. The research at home and abroad is mainly based on the therma...

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Problems solved by technology

[0004] At present, the capture of thermal desorption gas in the TAG system is still insufficient: the sample directly enters the GC analysis column due to the limitation of column length and detector, the thermal desorption flow rate is not high and the time is long, and the thermal desorption efficiency is low , and long-term continuous observation will pollute the chromatographic column and detector, affecting the service life of the chromatographic column and detector; under normal temperature conditions, the capture efficiency of the capillary column for low boiling point components is not high; semiconductor cold traps for high boiling point components The release requires longer heating time and temperature, which seriously affects the life of the trapping column, and there are problems of low resolution and residue of high boiling point components

For example, low-temperature cold traps do not release high-boiling point components completely, and there are residual problems. To improve the analysis efficiency, it is necessary to increase the analysis temperature and time, which will shorten the life of the trap tube; commercial cold traps mostly use ultra-low temperature refrigeration, electronic refrigeration and liquid nitrogen. Refrigeration method has a large volume, consumes refrigerant, and is difficult to meet the portable needs of observation; adsorbents can usually selectively adsorb certain types of organic matter, but continuous adsorption of samples with complex matrices will cause serious pollution problems. At the same time, this type of adsorption Tube replacement is often quite cumbersome

[0006] In order to avoid the pollution and residue of the chromatographic column / detection unit caused by the thermal desorption process of particulate matter, the present invention has developed a simple and practical online enrichment and analysis device and method for particulate organic matter

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