Trabalho com um GC 7890A e gostaria de saber como identificar vazamentos no injetor, sangramento da coluna e, como saber que minha coluna morreu?

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I work with a 7890A GC and would like to know how to identify inlet leaks, column bleeding, and how do I know my column has died?

I would like to know how to identify these things, because sometimes looking at the chromatogram or the baseline, it is not very clear to me if I am having loss of column efficiency or not.

Hi vitiin96,

this is very generic and any book on GC troubleshooting or the videos on the Agilent website could help. For the 7890 there is a troubleshooting manual available.

Good practice in GC is when you get a (new) column, you have an own suitability test like running a Grob test mix (or your own) and then identifying all parameters you want to log. If you think something is not ok after some time, you do the suitability test again and compare results.

For checking for inlet leaks you have to use a leak detector. If your carrier gas can exit the system, oxygen and/or water can enter it. Both can be damaging a column, especially at high temperatures, depending on the stationary phase.

Elevated baselines can come from column damage (see above) or from big analytes with a very long retention time (dirty columns). To get rid of late eluting compounds you follow the instructions on the columns test report. The you do the suitability test again. The contamination can also sit in the GC liner, constantly giving of unwanted compounds, replace it regularly.

When you compare the results of the tests and the area count for the same component has dropped to 50-60% (FID) of what it was, the column is dead. Same if the retention factor of a component under the same conditions is only half (TCD), the column is dead.

If everything fails, please call the Agilent Brazil office and have a CSD technical support export help you.

Success

Norbert

Oi vitiin96 

Eu faço parte do time técnico no Brasil, e qualquer dúvida adicional você pode também escrever diretamente para nós em contato.csd@agilent.com  

Obrigada!