When running partial 96 well plates ( ie 3 columns or 6 columns with the CO-RE 96) there has been sporadic instances of beads completely missing in a couple of wells in the destination plate at the end of the method. Looking back at the source plate and waste plate has no sign of them being. Has anyone experience this issue.
I have the CORE 2 tip adapter installed and the labware definition loaded.
The CORE 96 head is acquiring tips from the right side of the adapter ( front of the head columns 1 2 and 3).
I am suspecting that the tip is not fully seated and sealing but is sealing just enough to aspirate the liquid but is unable to dispense it ultimately to end up in the tip waste.
Do you normally teach the tip adapters? I have noticed the x and y can sometimes be off, but in terms of the Z do you leave that at the default?
When running full 12 column plates where tips are acquired from the tip wafers this issue has not been seen.
Any information/ insight/tips would be greatly appreciated!
thank you so much everyone and have a great weekend!!!
I usually use the snap on positions for the tip carriers and tip support. I try to avoid teaching these positions.
The way I usually troubleshoot this is by taking a video of the tip pickup and seeing if the tips are loaded evenly across the head (or part of the head). The z tip up could possible be an issue depending on which tips you are using as they are specific to each tip type.
Thank you so much @bowlineknot! Have you seen any issues with the X and Y using the snap coordinates for these positions? I have tried everything to try and make sense of this. The default Z coordinate is a bit higher than I thought it would be, which in some cases doesn’t fully eject the tip. In terms of acquiring tips off of the tip support the X seems to off with the channels favoring the west side of tip. The Tip wafers on the same carrier share the same X coordinate and nothing seems to be off there.
Interesting! It sounds like you may have some instrument hardware issues. I know that there’s an offset value for between the MPH and Channels. It’s also possible that the channels aren’t perfectly aligned that that can give you issues with tip pickup especially on the tip adapter.
Could you talk more about why you think your Z coordinate is off? When I eject tips onto the tip adapter it does it slightly above the final position of how the tips sit.
Two items you can take a look at if you haven’t already:
Check the positioning of the plate on the magnet and the pipetting parameters used to aspirate. If the tips are coming in contact with the plate, then it’s possible that the plate is being lifted slightly when using a partial pattern, yet being pinned to remain level when using all 96 tips.
For testing purposes, eject the tips to an empty tip rack instead of the waste to allow manual inspection for residual liquid inside the tips as further confirmation that the liquid is getting lost to the tip rather than elsewhere in the process. Depending on the volume of liquid and tip size, any remain liquid should not drip out in the time it takes to do this inspection. Additionally, most P200 handheld pipettes can fit well enough inside the shoulder of CO-RE tips to allow blowing out of any liquid.
While it is true we do not typically adjust the location of tip racks on the Deck Layout, the Tip Adapter is a bit of a special case in which minor adjustments are acceptable. If you haven’t tested with a lowered Z-coordinate, then I would suggest doing so after looking into the first two items.