Endrin Breakdown on my GC QQQ

Hello All,

I am running the 8890 GC, with 7010B TQ. I am analyzing PCBs and Pesticides on sediment samples. I am having trouble with my endrin breakdown.

After cleaning my inlet, installing a new column, new liner, etc. my Endrin breakdown is still high, way above 20%.

Does anyone have any recommendations as to conditions, liners, etc. that could help with this problem.

Thank you,


  • What inlet did you purchase?  

    What column, liner, O ring, septum...and how far up into the inlet did you install the column?

    How did you clean it? -- what procedure, products, tools, solvents, etc?

    And here is some light reading:

  • hi!

    We are using the MMI inlet.

    Column: DB-XLB, 122-1232

    Liner: Restek, Splitless. Single Taper with glass wool

    Septum: Agilent, Premium non stick, 5183-4757

    O-ring: Agilent, non-stick, 5188-5365

    Colum installed per procedure for inlet: 12-14mm.

    Inlet cleaned with brush and methanol.


  • Well you know I would personally blame a non-Agilent liner, right?

    As far as column up into the MMI, my recommendation is somewhere between 12 and 15.5 mm. A bit too high is definitely better than too low.

    Scrub the MMI:Multi Mode Inlet Cleaning Guide (agilent.com)  using the G3510-60820 MMI cleaning kit. The abrasive brush does OK for the bottom part, but isn't as great at the sides.  Take three cotton swabs like from the MS source cleaning kit, hold them together, dip them in solvent, and use them all to scrub the port - with the column out, of course.  It takes a bit of a touch to get them jammed in there without jamming them up, if you know what I mean.

    Solvents. I would use all the same solvents as ion source cleaning, not just methanol.

    and let us know. It might take a few cleanings to get it right.  Depending on the number of samples and their cleanliness, you may also need to clean the side-arm of the inlet and maybe even replace the copper split vent line.

  • Thanks for the tips!

    I just had a PM on the system and all the cleaning was performed, so I was hoping it would get better, but so far no luck.

    Do you think a liner without glass wool would be better? I'm trying different liners to see if those will make a difference.


  • It sometimes takes a few cleanings. Endrin breakdown can be problematic. Chemistry in action, right?

    The system can be fully functional - every piece of hardware is perfect - and still show breakdown. There's nothing to fix, nothing to replace, nothing to change, really.  Active sites in the sample pathway need to be removed. So you do normal user maintenance, then more advanced maintenance, then remedial maintenance - trying to do the least you can to get the necessary result at least in part so that you don't cause other issues.

    The list below is from the Stability Study paper referenced above.  The liner used was Ultra Inert, Splitless, no glass wool.  The list includes the vials, deactivated vial inserts and caps, too.  Consider Endrin all the way from the standards vial to when it comes out the end of the column into the MS.

    • Agilent J&W DB-8270D 30 m × 0.25 mm × 0.25 µm column (p/n 122-9732)
    • Agilent Ultra Inert inlet liner, single taper, splitless (p/n 5190-2292)
    • Agilent inlet septum, Advanced Green, nonstick, 11 mm (p/n 5183‑4759 for 50 pack)
    • Agilent ALS syringe, Blue Line, 10 µL, PTFE-tip plunger (p/n G4513-80203)
    • Agilent A-Line screw top vials, certified, amber; 100/pk (p/n 5190‑9590)
    • Agilent deactivated vial inserts, 5.6 × 30 mm, 250 µL; 100/pk (p/n 5181‑8872)
    • Agilent screw caps, PTFE/silicone/PTFE septa, cap size: 12 mm; 500/pk (p/n 5185‑5862)

  • Thank you so much for this info; i will keep trying. 

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