by
Ron » Thu Jul 10, 2008 3:31 pm
With the newer GCMS systems it is common to see light siloxanes from septa. This is more of a problem if mulitiple injections are made from the same vial. The problems tends to be worse wtih volatile solvents like methlyene chloride. One common source of the siloxanes is the rinse vials if they have septa. Change the rinse solvent often, and if the rinse vials have septa they should also be changed often. The best rinse vial tops I have used are the diffusion caps for the 4 mL vials that Agilent uses. I don't know if other companies sell these, but they reduce solvent evaporation without the use of a septum, and greatly reduce siloxanes in the rinse solvent.