Fully automatic thermal desorption instrumentIt is a high-precision and high-efficiency analytical instrument that works by using high-temperature technology to thermally analyze organic compounds in samples. During the analysis process, organic compounds in the sample will gradually evaporate with increasing temperature, and then be collected through condensation and collection. In addition, the fully automatic thermal desorption instrument also involves two key processes: heating and desorption. Heating is the process of heating a sample to a certain temperature, causing molecules on its surface to detach. This process requires temperature control to avoid excessive heating of the sample, which can lead to molecular decomposition or reaction; Desorption refers to the detachment of molecules adsorbed on the surface of a sample, which are then carried out of the sample by an inert gas flow (such as helium or nitrogen) and transported to a mass spectrometer or other detection equipment for analysis.

　　Fully automatic thermal desorption instrumentCore component maintenance:

1. Adsorption tube (sampling tube)

Cleaning and activation: This is the most crucial step. Used adsorption tubes must undergo thorough cleaning and activation to remove residual pollutants. Usually, the built-in "tube cleaning" or "aging" program of the thermal desorption instrument is used to bake for several hours at high temperature (usually 250-350 ° C depending on the adsorbent type) under a high-purity carrier gas (such as helium or nitrogen) flow.

Inspection and replacement: Regularly inspect the quartz wool at both ends of the adsorption tube for discoloration, sintering, or blockage, and replace it in a timely manner. Check if there are cracks or deformations in the adsorption tube itself.

Storage: The activated adsorption tube should be immediately sealed with a sealing cap and stored in a clean and dry environment to avoid contamination.

2. Focusing trap (cold trap)

Cleaning: The focusing trap is a component that is prone to contamination. Regularly (such as every 100-200 runs or based on baseline conditions) perform "empty run" or "bake" procedures, which involve high-temperature (usually 300-350 ° C) desorption of the cold trap without introducing a sample tube to remove residues.

Replace adsorbent: If the baseline noise remains high or the peak shape deteriorates after cleaning, it may be necessary to replace the adsorbent in the cold trap.

Refrigeration system: Ensure that the liquid nitrogen or electronic refrigeration system is working properly and the refrigeration efficiency meets the standard. Check the liquid level of the liquid nitrogen Dewar flask and replenish liquid nitrogen in a timely manner (if using liquid nitrogen refrigeration).

3. Transmission pipeline

Deactivation treatment: The transmission pipeline (from the injection port to the focusing trap, and then to the GC) should be kept in a deactivated state to prevent sample adsorption. Regularly inspect pipelines for leaks or blockages.

Cleaning: Removable transmission pipelines can be cleaned with organic solvents (such as acetone), then dried under high-purity nitrogen flow and baked at high temperature. For integrated pipelines, cleaning can be carried out through high-temperature baking procedures.

4. Injection port and six way valve

Sealing ring (O-ring): Regularly inspect and replace the O-rings at the injection port, valve, and joint (usually every 3-6 months or when a leak is found) to prevent carrier gas leakage. Use high-temperature resistant fluororubber or perfluoroether rubber O-rings.

Valve core: The six way valve is a precision component that avoids frequent manual rotation. If there is poor switching or air leakage, it needs to be maintained or replaced by professional personnel.