What to do if the gas chromatograph is contaminated

What should I do if the gas chromatograph is contaminated? Don\'t worry, just clean it. The specific operation method is as follows

 1. First, clean the gas pipeline. , then take this section of the pipeline out of the gas chromatograph. At this time, the dust on the outer wall of the tube should be cleaned to avoid pollution when the inner wall of the tube is cleaned. When cleaning the inner wall of the pipeline, it should be dredged with absolute ethanol first, which can remove most of the granular blockages in the pipeline and the organic matter and water easily dissolved by the pipeline. ethanol. In this stage of dredging, if the pipeline is found to be blocked, the earwash ball can be used to pressurize and purge. If this method fails to unblock the pipeline, an alcohol lamp can be used to heat the pipeline to char the blockageat high temperature in order to achieve the purpose of dredging.
2. After cleaning the gas pipeline with absolute ethanol, you should check whether there are any pollutants on the inner wall of the pipeline which are not easily dissolved by ethanol. Alternatively, you can heat the pipeline and purge it with dry gas, return the pipeline to the source gas path for use. If determined by the sample analysis process that there may be other pollutants that are not readily dissolved by ethanol on the inner wall of the gas path, other cleaning solutions can be selected according to the dissolution characteristics of the specific substance. The cleaning solution selection order should be to use the high boiling point solvent first, then use the low boiling point solvent to soak and clean. Alternative cleaning solutions include decalin, N,N-dimethylamide, methanol, distilled water, acetone, ether, freon, petroleum ether, ethanol, etc.
3. Cleaning the injector The cleaning of the injector must be preceded by dredging. Usually the blockage in the injector is the fragment of the injection septum, and the high carbonized boilers, these solid impurities can be dredged out with a stainless steel needle, then washed with ethanol or acetone. In order to make the cleaning more thorough, you can choose a mixed solution of H2SO4/HNO3/H2O=2:1:4 to clean the injector first, and then clean it with distilled water, acetone and ethanol. After cleaning, dry it, install the instrument and pass the carrier gas for half an hour, heat it to 120°C and wait for a few hours before it can work normally. When disassembling the injector, be careful not to break the lead wire of the heating element or make the lead wire touch the shell;the temperature measuring element should also be reinstalled to the original temperature measuring point after the injector is reinstalled. Usually the temperature measuring element and the heating body of the injector are in close contact, if the distance is too far, the vaporization temperature will be too high.
4. Cleaning the Detector
During the chromatographic operation, the detector is sometimes contaminated by the lost stationary phase and high boiling point components, easily decomposed components or corrosive substances in the sample, which requires cleaning The detector is cleaned. Cleaning can be divided into three situations. The first is that contaminated substances are limited to high boiling point components, which can usually be removed by heating the detector to operating temperature and then injecting a carrier gas. The second situation is that thedetector is only slightly contaminated, and steam cleaning can be used at this time. The process involves injecting tens of microliters of distilled water or acetone and other solvents into the injection port, and after 1-2 hours checking if the baseline is stable. The third case is when the above two simple methods cannot The deep cleaning method used to solve the problem requires the detector to be disassembled, and at the same time, an appropriate solvent must be selected, that is, i.e. the solvent must be able to dissolve the dirt without causing further pollution and damaging the detector. In addition, the cleaned parts should not be touched directly by hand.

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