Could blowout volume affect DNA concentration when pipetting on Hamilton Starlets

Hamilton (Venus) Venus Questions
1

We are having issues where it seems our robot is pipetting more liquid into the plate when our DNA samples have higher concentrations. Our plates have lyophilized liquid in them. We are thinking it’s the blowout volume. Any experience with this?

2

Do you find that the higher concentration samples are more viscous? Because that would certainly have an impact on the volume aspirated or dispensed. You may have to optimize the liquid class for viscous liquids if this is the case.

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3

I found that the submerge/aspiration height can dictate how much of the highly concentrated DNA sample is stuck to the outside of the tip and how much is subsequently transferred when dispensing into the destination container. Also the volume transferred for high concentration DNA samples may be lower than low concentration DNA samples especially in normalization workflows and you will have to set the lower limit of volume transferred according to tip types, 50uL/300uL/1000uL etc.

Depending on what your DNA sample compositions is: buffered water, solvents etc it can change how the DNA sample will behave in high vs low concentration. You may have to design separate liquid classes for each.

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4

When you say higher DNA concentrations - how high do you mean?

5

I don’t recall off the top of my head.

I suggest that you have some representative samples at low, mid, and high concentration that you expect in your process and test the liquid class and see how it performs to define the limits in your process.

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6

There really is no difference is viscosity that we can see, we are seeing issues with the 50ng concentrations

7

Around 50ng

8

This is what we have right now and we are still seeing this issue

10

-What is the volume of liquid that you are dispensing and are you sure that it is consistently a problem with just the high yield samples?
-How much extra volume is being dispensed with the high yield samples?
-Do you have a liquid class that you can share so we can see what’s being used currently? If it’s a low volume dispense (sub 10ul) you may want to work with your Hamilton Apps Scientist to create a specific liquid class for this dispense.