Enrichment-thermal desorption-chromatography separating unit

Abstract

The invention provides an enrichment-thermal desorption-chromatography separating unit. The enrichment-thermal desorption-chromatography separating unit is composed of a rapid enrichment thermal desorption device, a sample introduction device, and a rapid separating device; the rapid enrichment thermal desorption device is used for realizing low temperature enrichment of target components in gas samples using an adsorption tube at the action of low temperature of carbon dioxide gas, and realizing rapid heating thermal desorption via a heating wire, wherein an adsorbent is arranged in the adsorption tube, and the adsorption tube is enwound by the heating wire; after enrichment and desorption, the target components are delivered into the rapid separating device via the sample introduction device; a low temperature carbon dioxide gas cooling chromatographic column is adopted in the rapid separating device, relatively low chromatographic column initial temperature and relatively high heating rate are achieved via combination of the low temperature carbon dioxide gas cooling chromatographic column with a rapid heating module, so that high separation effect, extremely high analysis speed, and high peak capacity are achieved. The enrichment-thermal desorption-chromatography separating unit is capable of realizing on-line enrichment, rapid desorption, and super rapid gas chromatography of trace components in gas samples.

Description

technical field [0001] The invention belongs to the field of analytical instruments, in particular to a gas sample rapid enrichment-thermal analysis-chromatographic separation device. Background technique [0002] The analysis of trace substances in gas samples is an important part of analytical chemistry and environmental analysis. Its main application fields include: 1) Monitoring of volatile organic compounds (Volatile Organic Compounds, referred to as VOCs) in the air; VOCs in the air are harmful to human health, and lead to photochemical pollution and odor problems, so online and fast , Highly sensitive detection is of great significance. 2) The detection of trace volatile organic compounds in exhaled breath has great guiding significance for early detection, early diagnosis and screening of diseases. 3) On-line detection of hazardous compounds in the working environment, which is an important guarantee for safe production. [0003] Due to the complex composition, th...

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Problems solved by technology

[0005] 1. Enrichment at room temperature has low enrichment efficiency for low boiling point components

[0006] 2. The heating rate of the heater is slow, the long-term desorption process and the transmission line of the thermal desorption component cause the peak broadening of the thermal desorption component, which reduces the resolution ability of the chromatographic column to the peak, making qualitative and quantitative difficulties

Therefore, commercialized devices all use secondary cold trap and secondary thermal analysis technology, which will lead to a long analysis period and increase the cost and complexity of the device

[0007] 3. After the thermal analysis is completed, the time for the high-temperature thermal analysis tube to cool naturally to the initial enrichment temperature is too long, resulting in a long analysis period, generally more than 10 minutes

[0008] 4. The analysis period of the conventional chromatographic analysis method is too long, generally more than 15 minutes, which is not conducive to rapid analysis; while ordinary fast gas chromatography is difficult to ensure sufficient analysis rate, resolution and peak capacity at the same time, resulting in difficulty in balancing analysis speed and separation efficiency

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