CLLD failure with heated Samples

Hello everyone,

I am currently working on a Method where I aspirate liquid from Samples that are heated to 45°C. I use all 8 Channels to aspirate Out of two Tubes. The Tubes are pretty much filled to the top because I need a few milliliters. I noticed that with cLLD the Channels don’t aspirate in the liquid anymore when the Tube is about half empty (also No Error Message). With pLLD there is no issue. The cLLD sensitivity is medium. Do you think this Problem is because of the Temperature of the liquid and the cLLD detects wrong? The liquid is a Phosphate Buffer. I am Not very Happy to use pLLD because I need a Lot more Tips this way.


Hi Lisa,

Would it be possible to elaborate on what you are observing the channels doing when they are aspirating but not drawing liquid? Are they physically contacting the liquid surface but not drawing liquid? Are they starting the aspiration prior to reaching the liquid surface and drawing air?

If no errors are being triggered for ‘no liquid detected’ then errors are either being suppressed via programmatic error handling, or the channel is receiving a cLLD signal during aspiration in the allowed Z range. Sometimes this could be triggered prematurely due to droplets at the end of the tip.

With phosphate buffer, if there are excessive delays between aspirations when reusing tips, it is entirely possible for the end of the tips to dry out and plug with salt deposits, which happens and is easily remedied. Could this be the case? Are there any other materials suspended in buffer that could be contributing to clogs?

I do not think the temperature of the buffer is contributing to the issue here. Any additional details you can provide pertaining to the above would be helpful for determining what is happening here.



Hello Nick,

Sorry that I reply so late.
So here is what is happening:
I have two tubes filled with bacterial samples that were diluted in phosphate buffer. 4 tips each go into one tube and aspirate correctly the volume and then dispense it into other tubes. It takes some time because every tip of the 4 has to go into the same tube. After the dispensing I reuse the tips and then the error appears that the tips stop before they even touch the liquid and aspirate air.
With the pLLD everything is working fine. I did not try to use new tips with cLLD settings yet.
But maybe it is like you said and the channels get a false cLLD signal because of the salt residue.

There are also no suppressed errors in the method.

BR, Lisa