Interference of Toluene peak during GC Analysis

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 Description of Incident: 

During analysis of one of the Active content during GC analysis, peak interference of Toluene observed. 

Investigation: 


During Investigation it was found that in every injection on GC, peak of Toluene was eluting.

It was checked and found that Toluene was not used in that particular analysis then also Toluene peak was eluting.

To rule out the possibility of chemical contamination, new bottle of DMSO was opened. After using new bottle reagent also, Toluene peak was eluting  and no significant drop in area was observed.

Root cause: 

During further Investigation  it was observed that during previous analysis Toluene was used as an standard.  Currently the oven temperature  was kept as 120°C (as boiling point of Toluene is 110°C) to remove the traces of Toluene but then also Toluene peak was observed. 

Remedy : 

As a corrective action, oven temperature was increased to about 200°C and column condition done for about half an hour. After that blank was infected and no Toluene peak interference was observed. 

Conclusion:  It can be concluded that in case of any solvent peak is observed in blank then it can be coming from previous analysis traces which should be removed by running GC on high temperature for about half an hour.


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