Maintenance and maintenance of GC liner and inlet

When the liner or injection port is contaminated, it often causes changes in the chromatographic characteristics of the sample, such as peak asymmetry (tailing or forward extension), spectral distortion, and chromatographic peaks becoming smaller or disappearing.

The inner wall of the liner is contaminated, or there is debris on the injection septum, which easily leads to poor reproducibility of analysis results (such as retention time, poor peak area reproducibility) or ghost peaks

Improper filling of the quartz glass wool and other fillers in the liner, or the active sites on the inner wall of the filler and the liner can easily lead to poor repeatability of the experimental results

After the gas chromatograph has been running for a long time, solidified samples often remain in the injection port

①If the solidified sample remains on or under the injection septum, it is easy to cause the needle tip to be difficult to insert when the sampler is injecting; ②If the solidified sample remains in the part of the shunt pipe, it will cause the inner diameter of the pipe to become thin and even block; ③When the inlet temperature is much higher than the normal working temperature, ghost peaks may appear in the previously solidified sample, which will affect the reproducibility of the analysis results

In order to ensure the separation effect of the instrument, as well as the precision and accuracy of the analysis results, and to reduce the influence of contamination of the liner and injection port on the measurement results, it is necessary to maintain the liner and injection port frequently

1.

(1) Daily maintenance of the liner

(2) Regular maintenance of the liner

Generally, when analyzing polar samples, replace or silanize the liner and filled glass wool in time

2.

(1) Daily maintenance of the injection port

(2) Regular maintenance of the injection port

Regarding the injection septum, be careful not to overtighten it, and use a sharp-pointed injector

3.

(1) Cleaning of the shunt plate

(2) Cleaning of the shunt pipeline
.
During the maintenance process, no matter whether the shunt pipe is blocked or not, the shunt pipe needs to be cleaned
.
For cleaning the shunt pipeline, organic solvents such as acetone and toluene are generally selected
.
If it is difficult to clean the part of the shunt pipeline that is seriously blocked by simple cleaning, you can choose a steel wire of appropriate thickness to simply dredge the shunt pipeline, and then clean it with organic solvents such as acetone and toluene
.
Since it is not easy to make an accurate judgment on the condition of the shunt part in advance, it is especially important to clean the shunt pipe during the maintenance process for a gas chromatograph with manual shunt
.
For the gas circuit system (EPC) controlled by the pressure sensor and the flow sensor, the EPC controls the shunt.
Even if the small injection septum debris enters the interface between the EPC and the gas pipeline, it may block the EPC part
.
Therefore, the EPC part of the instrument must be checked every time it is repaired
.

Try to wear gloves during operation to prevent static electricity or sweat from your hands from affecting some components on the circuit board
.

Related links: Replacement of gas chromatographic deoxidizer and adsorption of organophosphorus pesticides on active sites of GC system