Heating desorption method of desorption tube

Abstract

The invention relates to a heating desorption method of a desorption tube. According to the method, a disposable activated carbon desorption tube is adopted, and the working state of thermal desorption is changed into three steps of preparation, desorption and manual sample introduction from four steps of preparation, desorption, sample introduction and aging. According to the characteristics of aworking sample, an automatic sample introduction function of equipment is abandoned and is changed into manual sample introduction which is more in line with the reality, so that the desorption process is simple, the detection result is accurate, the application range is wide, the desorption time is short, and the working efficiency is greatly improved.

Description

technical field [0001] The invention relates to the field of thermal analysis, in particular to a thermal analysis method for an analysis tube. Background technique [0002] Thermal desorption technology is to place solid, liquid, gas samples or adsorption tubes adsorbed with substances to be measured in a thermal desorption device. When the device heats up, volatile or semi-volatile components are released from the desorbed substances. It is an analytical pretreatment technology that enters GC and GC-MS into other analytical instruments through inert carrier gas. The general working state of thermal desorption is divided into four steps: preparation, desorption_desorption, sample injection and aging. The desorption time for a sample is too long, and the detection efficiency is too low. [0003] In general, for a thermal desorption device, the carrier gas flow that brings the desorbed sample in the sampling tube into the inlet is provided by the inlet EPC (electronic flow ...

AI Technical Summary

Problems solved by technology

[0003] In general, for a thermal desorption device, the carrier gas flow that brings the desorbed sample in the sampling tube into the inlet is provided by the inlet EPC (electronic flow control device), in order to quickly take away the desorbed sample The components require a large flow rate; however, a capillary column is installed in the injection port, and the column flow rate of the capillary column is generally small (1-3mL / min). The mismatch between the two flow rates needs to adjust the split flow rate of the injection port, which will reduce the detection sensitivity, and it may also cause the injection process to be too long, so that the sample peaks are tailed

In actual work, not all substances are like VOCS. Several or even dozens of substances are detected in one desorption injection. Some substances cannot be collected together due to the relationship between desorption temperature and their own properties. Only one desorption injection can detect Each substance will cause long desorption time and short detection time. Each substance is collected separately and desorbed one by one, but the process cannot be changed, which wastes the time of desorption and detection.

Images