By analyzing the cause of the contamination of the gas chromatography detector, a method of cleaning the detector with slight pollution was proposed; and a method of cleaning each detector was proposed for different types of detectors.

Key words: thermal conductivity detector; hydrogen flame ionization detector; electron capture detector; cleaning gas chromatograph consists of five parts: gas system, sampling system, separation system, detection system and recording system.

The gas is supplied by the high-pressure cylinder 1 as the active phase (carrier gas), the carrier gas is reduced in pressure by the pressure reducing valve 2, the impurities are removed by the purifier 3, the pressure regulating device 4, the flow regulating device 5, and the pressure and flow of the carrier gas are adjusted . The sample enters from the vaporization chamber 7 and is separated from the carrier gas through the column 8, and the detector 9 is converted into an electrical signal. After amplification, the chromatogram is recorded by the recorder, and the sample passes through the detector and is then vented. The detector is its core component. The function of the gas chromatography detector is to convert the components separated by the chromatographic column according to their properties and contents into easily measurable signals (such as resistance, current, voltage, ion current, frequency, light wave, etc.). These signals are sent to the data processing system to be recorded and chromatograms are obtained. The chromatograms are used for qualitative and quantitative analysis. If the detector is contaminated, the information provided will inevitably lack correctness. Inaccurate analysis results can lead to product obsolescence, waste of resources, and even scientifically incorrect conclusions. Therefore, once the detector is contaminated, it is important to choose the correct cleaning method.

Simple cleaning of the detector During the chromatographic manipulation, the detector is sometimes contaminated by the loss of the stationary phase and the high boiling point components in the sample, easily decomposed and corrosive substances, and it may not work properly. Therefore, how to clean the detector is proposed. The title of the device. If the contaminating material is limited to high-boiling components, the detector can usually be heated to the maximum operating temperature and then purged with carrier gas to remove it. Heating with detectors with radioactive sources requires extra care. For example, electron capture detectors usually made from helium sources generally cannot exceed 200°C. In addition, care should be taken that the temperature of the heating does not damage the detector's insulating material. If the heating method is not suitable, you can also use a pure acetone solution from the injection port injection (can be injected into tens of microliters each time) for cleaning, which is effective when the degree of pollution is light.

If none of the above methods can solve the pollution problem, the detector should be unloaded for more thorough cleaning. Select the appropriate solvent first, and then both dissolving the contaminants and not damaging the detector. Use a syringe to inject the detector into the measuring cell for cleaning. If conditions permit, use ultrasonic cleaning.

The gas is supplied by the high-pressure cylinder 1 as the active phase (carrier gas), the carrier gas is reduced in pressure by the pressure reducing valve 2, the impurities are removed by the purifier 3, the pressure regulating device 4, the flow regulating device 5, and the pressure and flow of the carrier gas are adjusted . The sample enters from the vaporization chamber 7 and is separated from the carrier gas through the column 8, and the detector 9 is converted into an electrical signal. After amplification, the chromatogram is recorded by the recorder, and the sample passes through the detector and is then vented. The detector is its core component. The function of the gas chromatography detector is to convert the components separated by the chromatographic column according to their properties and contents into easily measurable signals (such as resistance, current, voltage, ion current, frequency, light wave, etc.). These signals are sent to the data processing system to be recorded and chromatograms are obtained. The chromatograms are used for qualitative and quantitative analysis. If the detector is contaminated, the information provided will inevitably lack correctness. Inaccurate analysis results can lead to product obsolescence, waste of resources, and even scientifically incorrect conclusions. Therefore, once the detector is contaminated, it is important to choose the correct cleaning method.

The thermal conductivity cell detector (TCD) cleaning thermal conductivity cell detector consists of a cell body and a Wheatstone bridge circuit, as shown in FIG. The cause of the contamination is: the chromatographic column may cause the loss of the stationary phase at high temperature; the high boiling point component of the sample, the easily decomposed and corrosive substances, and the lower cell body for improving the sensitivity of the thermal conductivity detector. At the temperature, the sample under test may condense in the detector. The detector will not work after being contaminated, and the detector must be cleaned to ensure that the test results are scientific and highly accurate. The cleaning method is: fill the measuring tank of the detector with acetone, ether, decahydronaphthalene and other solvents, soak it for a period of time (about 20min), then dump it, and repeat it repeatedly until the solution that has been poured out is relatively clean. When a solvent is used, it cannot be washed. According to the nature of the contaminants, the high boiling point solvent is used for immersion cleaning, and then the low boiling point solvent is used for repeated cleaning. After washing, rush to the solvent, install it on the instrument, heat the detector, and use the carrier gas for several hours.