Methanol GC contamination

Hi SteffiGC, 

Try to do a 'no-inject' blank to evaluate if your carry-over is coming from the ALS or the inlet.  You can do this by removing the syringe from the injector and running the method as normal - be sure to flip the syringe clip over the carriage so it isn't flopping around.  If you see peaks, the contamination is likely in the inlet or column.  You could replace the septum and liner, trim the column and re-test.  If  no peaks are present when the injector isn't used, replace wash vials, empty waste vials, and wipe down the tops of your vial caps.  Its also a good practice to wipe off the syringe foot.  Sometimes high concentrations of sample can accumulate there.  Let us know what you find out!

Abbey

Hi SteffiGC, 

Try to do a 'no-inject' blank to evaluate if your carry-over is coming from the ALS or the inlet.  You can do this by removing the syringe from the injector and running the method as normal - be sure to flip the syringe clip over the carriage so it isn't flopping around.  If you see peaks, the contamination is likely in the inlet or column.  You could replace the septum and liner, trim the column and re-test.  If  no peaks are present when the injector isn't used, replace wash vials, empty waste vials, and wipe down the tops of your vial caps.  Its also a good practice to wipe off the syringe foot.  Sometimes high concentrations of sample can accumulate there.  Let us know what you find out!

Abbey

Hello thanks for answering ! It was bad luck and also a heptane bottle contamination.. at the same time i had a high value sample so i thougt it was that but it was the bottle aswell 

Aha!  It happens to all of us on occasion.  Thanks for updating the forum!