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The proficiency of manual injection technology in gas chromatography also directly affects the quality of the analysis. The main requirements for good injection techniques are:
1 injection speed is fast
Slow injection speeds can lengthen the vaporization process of the sample, causing the sample to broaden into the initial band of the column.
2 Sampling is accurate and reproducible
The sampling volume should be accurate, and the speed of sample extraction should be reproduced to ensure the reproducibility of the injection. Especially for samples with high viscosity, avoid forming bubbles in the syringe.
3 Avoid mutual interference between samples
If there is a residual component of the previous sample in the syringe during the injection, it will interfere with the analysis of the next sample, resulting in a quantitative error. This is called the memory effect in the chromatogram and must be eliminated.
In the gas chromatograph analysis, the Zui is usually a 10 μL micro syringe, and the injection volume is generally not less than 1 μL. If the injection volume is to be controlled below 1 μL, a 5 μL or 1 μL syringe should be used.
5 Reduce injection discrimination
Injection discrimination refers to the fact that the solvent in the tip and the volatile components in the sample first begin to vaporize when the needle is inserted into the gas chromatograph inlet. The content of high-boiling components in the sample entering the column may be lower than the actual sample, causing errors in quantitative analysis.
This is the end of the introduction of What should I pay attention to when I need to manually enter the gas chromatograph. I hope it can help you.