GC maintenance method
Add the Time:2019/4/26 15:05:43
Quantitative gas chromatography is often used in organic analysis instrument in the running for some time, due to electrostatic reasons, inside the instrument more easily absorbed dust; circuit boards and circuit board connectors in addition to adsorb dust, but also regular and certain organic vapor adsorption together; because of the lower portion of the freezing point of organic matter, in the inlet position often find solidification organics diversion pipeline in use for some time, an inner diameter thinning, even organic clogged; during use, TCD detector is There may be organic pollution; FID detector time for organics analysis, organic deposition or nozzle position of the nozzle or collector, the collector part of coke frequent occurrence.
1 inside the instrument purge gas chromatograph after cleaning shutdown, open the sides and rear of the instrument panel, were purged with instrument air or nitrogen dust inside the instrument, to a greater or dusty places not easily purged with a soft bristle Brush with the handle. After the purge is completed, the internal instrument where the presence of organic pollution of water or an organic solvent to scrub, water-soluble organic substances can be wiped with water, a place that can not be thoroughly cleaned with an organic solvent can be treated for non-water-soluble or may the occurrence of organic chemical reaction with water with an organic solvent not react with cleaning, such as toluene, acetone, carbon tetrachloride. Note, you can not wipe the instrument during the secondary pollution caused by corrosion or surface of the instrument or other components.
The first two circuit boards maintenance and cleaning GC prepare overhaul, cutting off power to the instrument, first with instrument air or nitrogen to the circuit board and the circuit board slot purge, use a soft brush with the board and the slot purge in dusty parts carefully cleaned. During operation try to wear gloves to prevent static electricity or hand perspiration, etc. affect the part of the components on the board.
After the purge is completed, the board should be carefully observed usage, see the printed circuit board or electronic components for visible corrosion phenomena. Circuit board contaminated with organic electronic components and printed circuits carefully wipe with cotton dipped in alcohol, board interfaces and the slot portion also wipe.
3 Inlet cleaning overhaul of GC inlet glass liner, gold seal, the inlet flow line, EPC and other parts are cleaned is necessary.
Glass liner and gold seal of cleaning: Carefully remove the glass from the instrument liner, tweezers or other gadgets Carefully remove glass wool and other impurities within the liner, Pipette process not to scratch the surface of the liner.
If conditions permit, can be preliminary cleaned the glass liner in an organic solvent with ultrasonic cleaning, drying after use. Also can be cleaned with acetone, toluene and other organic solvents, dried after cleaning is completed can be used.
Shunt plate is the most ideal method of cleaning sonication in a solvent, used after drying. You can also a suitable organic solvent cleaning: After removing the gold seal from the inlet, the first use of an inert solvent such as toluene wash, alcohol solvents such as methanol and then washed, dried and use.
Bypass pipeline cleaning: When gas chromatograph for analysis of organic matter and a polymer compound, the lower the freezing point of many organic compounds, from the gasification chamber via the sample flow line venting process, part of the organic matter in the flow line solidified.
GC after a long period of use, the inner diameter becomes gradually smaller flow line, or even completely blocked. After the flow line is blocked, the instrument displays the inlet pressure abnormalities, poor peak shape, analysis of abnormal results. In the repair process, regardless of whether the judge in advance whether the flow line clogging, need for bypass pipeline cleaning. Bypass pipeline cleaning generally choose acetone, toluene and other organic solvents, severe blockage of flow line sometimes simple cleaning methods are difficult to clean, need to take some other auxiliary mechanical methods to complete. You can the appropriate wire thickness of the flow line simple and clear, and then use acetone, toluene and other organic solvents for cleaning. Thanks in advance is not easy to divert part of the case to make an accurate judgment on the manual bypass gas chromatograph, in the repair process is necessary to split pipeline cleaning.
For EPC control shunt gas chromatograph, due to prolonged use, it is possible to make some small crumbs into the EPC septum and gas pipeline interface, is subject to the EPC partially clogged or cause the inlet pressure. Maintenance process as much as possible so every part of the instrument EPC check with toluene, acetone and other organic solvents for cleaning, and drying.
Since the injection and other reasons, the inlet of the outside at any time condensation may form part of the organic matter, the available cotton wool dipped in acetone, toluene, and other organic matter on the inlet preliminary cleaning, then the removal of the first organic indelible mechanically, Note the removal of organic matter solidification process must be careful not to damage the instrument parts. After the solidification of organic matter removal, with an organic solvent and then carefully wipe the instrument components.
Samples of sediment or other substances 4TCD and FID detector cleaning TCD detector during use may be entrained in the column effluent contaminated. Once TCD detector is contaminated, the instrument baseline jitter, noise increases. It is necessary to clean the detector.
HPs TCD detector thermal cleaning methods can be used, as follows: Turn off the detector, the detector is removed from the column header, the column header inside the detector block blocked with dead, with reference to gas flow settings to 20 ~ 30ml / min, set the detector temperature was 400 ℃, thermal cleaning 4 ~ 8h, it can be used after cooling.
Domestic or Nissan TCD detector contamination using the following method. After the instrument downtime, the TCD gas path imported removed, followed by acetone (or toluene, can choose different solvents depending on the chemical nature of the sample) with 50ml syringe ethanol, distilled from the intake port repeated injection of 5 to 10 times, Fall ball slowly withdrawing from the intake port of the blow, blow impurities and residual liquid, and then re-install the inlet connector, rose to power after the column temperature 200 ℃, the detector temperature rose to 250 ℃, through the operation ratio analysis 1 to 2 times the flow is large carrier gas until the baseline is stable.
For serious pollution, the outlet may be blocked with dead block, filled with the acetone from the intake port (or toluene, can choose different solvents depending on the chemical nature of the sample), hold for about 8h, liquid effluents, and then treated as described above .
FID detector cleaning: FID detector in use, good stability, the requirements are relatively low, the use of common, but in the long process, it is easy to detect nozzle and collector coke and other problems, or organics or collector nozzle at the deposition conditions. FID organic deposition of coke or other issues, can be detected and collector nozzle with acetone, toluene, methanol and other organic solvents for cleaning. When coke thicker can not be cleaned, they can of coke thicker portion detector careful sanding with fine sandpaper. Note sanding process should not damage the detector. After the initial grinding is completed, the pollution section further wipe with a soft cloth, and finally washed with an organic solvent, usually can be removed.