Problem with Diphenylamine

[astroguille]

Hi people!

I analize pesticides (Multi-Pesticide Residue Analysis) in fruits, vegetables, water and soil with an Agilent GC6890/MSD5973. I use a column HP5ms.

I have a problem with Diphenylamine: this pesticide appear in almost every samples (in blank samples too).

I changed the septum and the liner, without success results.

The system is contaminated, but I don't know where.

Please help!

[AICMM]

astroguille,

Because of the blanks, start with solvent. Go to a different one, not the same type from a different vendor but a different solvent.

Then, you name it, syringe, waste vials, rinse vials, rinse solvent, split vent line, front of column,.....

Best regards.