End aspiration step before the Channels retract


I am aspirating/dispensing out of small ports in my labware. I need to make a decently tight seal between the pipette head and the ports of the labware to achieve robust aspiration. Because this seal is quite tight, sometimes after aspiration the retract motion lifts the labware (bad). I believe if I could add a slight shake after aspiration and before I retract, I could break this stiction and prevent the lifting behavior. I would like to aspirate, end the aspiration step (before retracting), execute a move command to perform the shake, and execute a move command to return to a safe z-height.

What would be the most elegant way to do this? Will I have to perform all these steps via firmware commands?


Hi Devin,

I don’t think that is possible, unless you would program the full aspiration command with individual firmware commands, which I really wouldn’t recommend.

I think you have two options:

  1. Use a downholder module that fixates your labware so it is not being pulled upwards
  2. Slow down the retract speed to allow the tip to exit the labware

I have worked with pre-slit septums on a Hamilton previously and that required a small clip that prevented the labware from being lifted.

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Hi Ben,

Thanks for your reply. Is the downholder module you recommend Hamiltons “PCR Plate Hold-Down” Carrier ? Are there other modules you recommend? I have not used anything like this in the past.

Hi Devin,

If it would be possible to share details or even an image of the particular labware in question, I can help to advise on down holder options as @benjaminwohl suggested, which is likely the best route to go for this scenario.

Does this labware need to be moved/transported during the run?



Hi Nick,

I found this pdf which is an application note on an exetremely similar application. Here are some images of the labware:

You can see the small circular ports I aspirate and dispense through. The ports require the tight seal I mentioned in my earlier post. The labware remains stationary. Holding down the labware would be great but contact would need to be made against the outer edges of the dialysis device (white device in the wells of the deep well plate). Any ideas are appreciated!

I have used these from Telos: Hold Down Module - Telos Scientific. I am not sure if they have a deep well module readily available OTS, but may be worth asking

I see. We have a MFX downholder module that may fit your requirements. PN 188313 - often used for Matrix tube racks, but can be used with other SBS formats as long as the total height of the labware is less than 47.1mm. The function is to keep underlying labware pinned in place when tips need to access slim enough containers.


The top frame of the holder is made for typical 96 SBS format, so the spacing of the dialysis ports as they are seated in the 48 DWP would need to be compatible or close to compatible with typical 9mm by 9mm SBS 96 format spacing for the ports to be accessible through the surface of the frame. Looking at the your image, this seems probable, but I cannot find a technical drawing to confirm.

The downholder MFX module is fully amenable to walkaway runs if needing to process multiple plates. CO-RE grips (or QCG for VANTAGE) can be used to unlatch and move the top frame, which can be parked in a plate locator, at which point your plates would be transported to/from the processing position underneath. See below for loaded and unloaded on-deck configurations.

If you are interested in using this as a solution, reach out to your sales rep and they can help get the ball rolling. If it would help to be pointed in the right direction, let me know and I would be happy to provide contact info. Additionally, if you were willing to ship an unused sample of the labware, Hamilton can confirm that the spacing will work prior to purchasing. Your sales rep can help to facilitate this as well.



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Thank you all for your help! I will reach out to my Hamilton sales rep.

@NickHealy_Hamilton would you happen to have any further information on this Hamilton/Scienova technical note ? This note implies they have complete automation of the process. Maybe someone who worked on this project would have some insight into the problem I am facing? Thanks again for the help.

I will follow up with our colleagues in Europe and try to get more information! I will keep you posted!


Thank you, Eric!

Hi @djunk,

We followed up with our colleagues, and while the project referenced by the application note only got as far as the early testing stages, I am able to share some of their findings. To this link I uploaded the labware definition, liquid class, pipetting parameters, and teach location they used to aspirate from the dialysis wells. There isn’t anything particularly special about the techniques used, but using 1000uL tips served their purposes best, likely due to the larger diameter.

Let me know if you have any questions.

Thank you,

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Hi Dan,

Thank you for this resource.