Cleaning and maintenance of three gas chromatography detectors

related topicsDuring the operation of
chromatography
, the detector is sometimes contaminated by the fixed phase loss and the high boiling point components, easy decomposition and corrosive substances in the sample, so that it can not work properly, so the problem of how to clean the detector is raised. If the contaminated substance is limited to high boiling point components, the inspector
heated
to the maximum temperature of use and then loaded with air can be removed. When using a radiological detector heating to be more careful, for example, usually made of radon source electronic capture detector generally can not exceed 200 degrees, in addition to the heating temperature can not damage the detector's insulation material. If the heating method is not suitable, it can also be used pure acetone and other solutions from the inlet injection (can be injected tens of microliths at a time) for cleaning, which is effective when the degree of contamination is less.If none of the above methods can solve the problem of contamination, the appraizer should be removed for more thorough cleaning, first select suitable solvents, to dissolve the dirt, but also can not damage the identification device, with syringe injection into the measuring pool for cleaning. If there are conditions, with super-raw wave cleaning is more ideal, pay attention to: the cleaned part can not be touched by hand.I. The cleaning of the thermal conductivity detector fills the measuring cell of the tester with solvents such as acetone, ether, and ten hydrogen proponents, soaks for a period of time (about 20 minutes) and pours out, so repeated many times until the poured solution is relatively clean. When a solvent cannot be washed, the high boiling point solvent can be used for immersion cleaning according to the nature of the dirt, and then repeatedly washed with a low boiling point solvent. After washing the heat to rush the solvent, and then installed on the instrument, heating detector, air flushing for a few hours can be used.II, hydrogen flame ionization detector cleaning when the contamination is not too serious, you do not have to remove the cleaning, at this time only need to remove the
-spectrum column
, with a tube will enter the sample port and the detector joint up, then carry the gas and raise the detector furnace temperature to more than 120 degrees, from the inlet first injected about 20 microliths of distilled water, and then with dozens of microliths of acetone or fluorine (Freon 113 and other) solvents for cleaning. At this temperature to maintain 1 to 2 hours to check whether the baseline is stable, if still not satisfied can repeat the above operation or remove the cleaning.when the contamination is more serious, the cleaning must be removed. First remove the collection pole, positive pole, nozzle, etc. , if the nozzle is made of quartz material, first put it in water for immersion overnight. If the nozzle is made of stainless steel and other materials, can be made with electrodes, etc. , first carefully polished with fine sandpaper (300 to 400 s), and then with appropriate solvents (soaked such as methanol and benzene 1:1), you can also use
ultrasonic cleaning
, and finally with methanol cleaning, placed in the
oven
drying. Be careful not to use halogen-containing solvents (e.g. chloroform, dichloromethane, etc.). To avoid acting with Teflon materials, resulting in increased noise.parts after washing, take them with tweezers and do not touch them by hand. Be careful when drying and assembling, or you will get stained again. After loading the instrument, the air is loaded for 30 minutes, and then the ignition raises the temperature of the test chamber, preferably after 120 degrees for several hours before rising to the operating temperature., the cleaning of the electronic capture detectorthe electronic capture detector has a radioactive source, usually Ni63, so be especially careful.the detector has radioactive foil, and then wash the metal and Teflon parts of the detector with 2:1:4 sulphuric acid, nitric acid and aqueous solution. When the cleaning fluid is clean, wash with distilled water, wash with acetone, and dry in an oven about 100 degrees. For H3 source foil, wash first with hexane or penane, never wash with water. Waste liquid should be diluted with a large amount of water and discarded. The Ni63 source should be more careful, must not contact with the skin, can only be operated with long tweezers. First wash with ethyl acetate with sodium carbonate or with benzene, then soak in boiling water for 5 minutes, remove drying, loaded into the appraizer. Load the instrument and load the gas for 30 minutes, then rise to the operating temperature, a few hours later standby. The remaining waste liquid must be diluted with a large amount of water before it can be discarded.