Hi Everyone,
I’m trying to optimize an Empty Tip liquid class for MCA96 with 200uL tips and I’m really struggling to slow down the speed of the dispense. It seems like any changes I make to the dispense acceleration, deceleration and/or dispense speed in the microscript do not make much of a difference, so it feels like I’m missing something here. Any idea what I’m doing wrong?
Is this the brand new MCA head?
yes
To give a little more context, I’m trying to empty tip contents back into a deep-well plate after a multi-dispense loop. Clearly the dispense speed is too fast because I’m seeing a lot of backsplash onto the tips. I’m using liquid sensing with submerge depth set to 4mm. I’ve decreased the dispense acceleration, deceleration and speed all the way down to 1, 1 and 0.1 respectively, and it still feels like it’s shooting the excess liquid and leading air gap way too aggressively.
Is this a custom Empty Tip script? Using 1mL tips?
It’s a custom empty tip liquid class using 200uL filter tips. I started with a blank microscript. Also, FYI - I’m totally new to scripting and liquid handling.
Is there volume in the deep-well plate that you’re dispensing back in and how much are you trying to dispense back on average?
I would consider adding a fixed tip touch into the liquid instead of cLLD and slow down the movement out of the well from 60 to like 30.
Yes there is volume in the deep-well plate. The volume varies depending on the script and iteration of a multi-dispense loop, that’s why ideally it would be more convenient to use cLLD. Volume will vary from 1000-100uL. Dispense volume back into the deep-well plate is ~10-25uL with 10uL leading air gap.
If the volume varies across your destination plate, I am not sure that I would recommend using cLLD with your MCA96 or you will get some bad detection values.
Open a helpdesk ticket and they’ll further clarify the detection logic.
Ok, thanks for your feedback.
Just a few points / questions here.
I know this may seem obvious, but when I first started scripting I, notoriously, would adjust liquid class scripts to find out nothing was happening when applied to my run script. I was forgetting to change the liquid class to the appropriate tips, 200uL filtered in your case, when making adjustments.
Just something simple to double check, although you mentioned the entire microscript was from scratch, so this is likely not the issue here.
I understood from the Liquid class training that the MCA96 uses only the first tip that detects a liquid to set the liquid level. So if you have variable volumes in one plate then only the highest volume inside the labware will be used for the calculation across ALL wells/tips
This was not my initial experience. When I tested 1 channel with 1 tip in a 96 well plate it was pretty good but when I tested multiple channels with some empty wells, it was returning strange detection values or prioritizing the lack of detection for those channels over the channels that had wells with liquid.
Also technically they only recommend using the MCA96 detection with troughs and not 96 well plates for now.
In the script I’m using the empty tip function. Surprisingly, I don’t have any issues with liquid level detection using the MCA96 to dispense back to the 96-deep well plate. The issue I have is slowing down the speed of the liquid dispense using the empty tip function & empty tip liquid class.
