1260 Autosampler wetting whole needle assembly when assembly sits in needle park station - how do I stop it?

I am performing an online derivatisation (per Agilent App Note 5994-1915EN for Thiamine) with the 1260 autosampler chilled to 4C. Between injections the needle assembly sits in the needle parkstation (approx. 6 minutes) and while it is in there, the whole area gets wet and the plastic assembly gets covered in liquid, regardless of whether "Standard Wash" is selected or "Off" is selected. I fully dry the assembly while it is performing the mixing steps, and every time the needle releases from the park station to go to Vial 1 for the Methanol, it has enough liquid on it to fill up the divot in the septum of the reagent and sample vials and drip all around the vials and around the parkstation. If I ignore it, it takes about 10-15 injections before there is enough liquid in the leak tray to trigger a leak shutdown. Can anyone tell me where the wet is coming from? It isn't a usual leak as if I just leave the method running without doing injections no leaks occur. I just started at this lab and they had the needle wash turned off and the wash bottle completely empty but no one knows why. I added a flushport wash and turned off Standard Wash but the assembly is wet before it gets to the flushport.

Please help - what could be causing this?

Thanks, Sarah.

Parents Reply
  • Our autosampler is the G7167 multisampler, where the whole needle assembly is dropped off and picked up by the arm that also moves the sample trays. The area getting moisture on it is higher up than the needle wash - see image - the yellow box is the needle seat, the parts of the needle and assembly getting wet during the run is in the red box. Also, residue left on the solvent vials and on the needle parkstation indicate the liquid is at least partially made up of the buffer, not only the wash liquid (milliQ).

     autosampler image

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