Liquid level detection with fluent control

anyone has experience on liquid level detection (e.g. 96 well) and mainly on improving accuracy and repeatability? this is done so far by fixed tip of tecan fluent and noticed some variations between tips

Is the labware container definition optimized?

Also sometimes the properties of the liquid impact the detection.

1 Like

Sometimes the detection may be very because of some unexpected gaps of the plate with its base. The production of plate is not perfect, resulting in some uneven gaps, then result in detection variations.

any reference or procedure on how to optimization labware definition? we are using water for now. not sure if search speed in the liquid detection command would be helpful?

How much variation are you seeing? At what volumes?

Also see this post for similar troubleshooting:

It’s for the EVO but many of the advice carries through regardless of platform.

2 Likes

In my struggles with inaccurate labware ‘compartment definitions’ I have created a script that will perform liquid level detection on X number of wells (defined by user) in a labware.

This worked quite well, but I also found that some of the received labware definitions from TECAN were way off. The compartment definitions on 96 well plate were quite spot on. I am now working on a scrip that will pipette volumes min-max in X steps so that I can optimize the well compartments. I have one 2mL deep well plate that has 5 different well sections (partial cone, cylinder, then concave square, then square, etc). Not easy to get the volume correct for that one, but will be working on that soon and then I’ll upload the well definitions.

Is anyone willing to share screenshots of compartment definitions and plate name/product IDs to improve volume detection?

As for other Liquid Handlers, the QIAsymphony (that uses the same 2mL deep well plate as I’ve been using for the Tecan) works the other way round. It will detect liquid at a certain level and then based on the tip height calculates and interpolates the amount of volume (there is a preset height and volume table incorporated in the protocol of the machine).

Dirk

1 Like

Here is an example of the Tecan Fluent ‘Compartment Definitions’ of the well for a ‘Eppendorf twin.tec PCR plate 96 skirted’

Would any compartment definitions do here or are you looking for something in particular?

Nothing in particular. I would say that any compartment definitions that you know is good would suffice. If you share, then please add the specific plate type and the definitions :slight_smile:

I would like to see this as an opportunity to share some ‘Compartment Definition’ values so that others can use that as a base to work on. In my opinion a well defined labware would make all the difference in a lot of processes.
I have seen a few times that specific volumes were transferred (ie. 50uL) and then these values are set for the specific wells, but then when measurements are performed the volumes are automatically updated in the process and then in-situ normalization fails (meaning: is performed with the incorrect volumes).

Hope this makes sense.

Newer versions (Since FC 3.0. I think?) allow you to bypass the compartment definition and define volume = height datasets directly. That might be an easier way to fine-tune the exact liquid level work you’re doing than recreating the labware completely. It would work well with that ~min-max in X steps~ function you were talking about (unless that was what you meant, and I misinterpreted the entire post)

Besides that, I often request technical drawings of labware from manufacturers if it’s a very precise teaching needed. Sometimes they provide CAD as well! Without the CAD it’s difficult to know exactly the tapering of wells from top tube diameter to bottom, but typically its ~1° in most labware.

Could you elaborate on how to bypass the compartment definitions? I’ve found the functions ‘calculateVolume’ and ‘calculateHeight’ and that would allow me to grab a the height from a well and then compare to a stored file somewhere. But this would mean creating a template file, then get the height, search in the file (interpolate) and then return data value to the well. Not something to script just on the fly.
Is there a template that you can select in Fluent Control that will calculate automatically? I can not find it anywhere.

As for the supplier… I’ve e-mailed them 3 times already, but so far I’ve received two files from 2 different plates. Seems that some providers are not as forthcoming with sharing their labware details.(that is why I posted this). If we have compartment definitions that work… Hey, why not share with other users?

if you go to the compart definition section, the dropdown contains a “user defined” option
here you can import from a file
the file (.csv") needs 2 x fields, separated by a “;”

example is below:

1.2;100
7.2;400
11.2;650
13.2;820
15.2;1050

the “calculate” height & volume functions utilize the compartment definition settings - this definition is the key to accurate calculated volumes

4 Likes

I tend to go with the manufacturer specs because that’s the ideal. The reality is that plastics will vary.

In the past I’ve tried to get exact definition for all Labware but that was just a… suboptimal use of my time. Furthermore you have an interplay of forces that can impact detection data like detection variables or meniscus or bubbles alongside plastics variability.

New Tecan’s have new features to make detection easier (MultiSense, PMP AI, Phase Detection, pLLD and more on the roadmap…) which gives the operator a ton of potential power when combined with the micro script.

I haven’t had a lot of time with these new features tho so I’ll report back if I do.

Found it… That makes it super easy to optimize for a DeepWell with > 5 different shapes inside the compartment. Just pipette different volumes into the plate, perform height detection on all, and then feed the data into the ‘user defined’ table. Way better then trying to recreate it from scratch.

2 Likes

how do you measure height?

  1. I will pipette different volumes in a plate (all 3 or 4 times for averaging)
  2. place on Tecan and measure volume inside each well
  3. loop over each well and convert the volume to height and place as meta-data in each well
    • use function calculateHeight(labwareName,well, compartment,volume)
  4. Export the labware information and then volume and Z-height are available.
    • volume and height in this case
1 Like