Sample error code 245

Having an issue with injection from the autosampler. In the last 24 hr it has bent two plungers and giving a Sample error code 245 - Autosampler front tower plunger error. Any advice on how to begin trouble shooting this? We are running the GC/MS 7820A.

  • Bent plungers are typically caused by a sample or solvent that gums up the syringe.  What type of samples are injected and in what solvent?  What solvents are used for your syringe washes A and B in the sampler?  How many pre and post injection solvent washes are setup in the method?  What syringe type are you using - does it have a PTFE tipped plunger?

  • Thank you for getting back to us so quickly Paul. The samples consist of a 2% dilution of ethanol and acetonitrile in water, wash solvent B is distilled water with 6 pre and post injection washes (the method we have been running does not use wash solvent A, which for us is normally methanol). The syringe is a Agilent gold standard syringe (P/N 5181-1267 10uL FN 23-26/42/HP, Batch 44X-107180M). We are not certain if this is PTFE tipped or not, but you may have a better idea of that given this information.

  • 5181-1267 - plunger tip material - stainless steel.   I'd switch to a PTFE tipped plunger like 5181-3354 .   Using water as the last rinse may be the culprit. I've known of this problem happening on Monday after a syringe sits after just water in it from Friday, but overnight seems short.  Try using Wash Solvent A as water and Wash Solvent B as something like IPA or hexane so that the last rinse is not water.

    Another simple thing to try is to make a method that you can load at the end of every sequence like "Plunger Saver.M" or something simple where that run is the only time it uses the alternate syringe wash solvent and then have it do maybe ten washes.  Just load an empty last vial, inject 0.1 µL, and the run only needs to be 0.1 minutes or so.  You could expand that idea, have it actually inject solvent, and then use that last method as the bake/cleanup every day.

    Let us know if it happens again after the solvent change...

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