Hamilton- piercing through membrane Issues

Hamilton (Venus)
1

Hello,

I’m encountering an issue with piercing through a membrane when aspirating whole blood. I’m currently using 1mL tips, which I can pierce successfully. However, due to the pressure inside the tube, the whole blood contaminates the stop disk and sometimes enters the pipette. I’m using 1mL filtered tips, and my current method involves piercing through the membrane 4 times and, on the 5th time, aspirating.

Does anyone have any suggestions for the best approach to pierce through the membrane without contaminating the pipette?

2

Hi I don’t know if this would fit in your protocol but Hamilton makes Piercing Tips which don’t actually behave as pipettes and thus you don’t have to worry about contaminates entering the air displacement path. https://www.hamiltoncompany.com/automated-liquid-handling/consumables/platform-consumables/coreii-tips/piercing-co-re-tips

3

Depending on how much overpressure you have, you could try and aspirate air above the liquid levels during your first piercing steps. Maybe this works out for you?

4

Thank you, Sam,
I will try using piercing tips to pierce the membrane and then use 1mL tips to aspirate.

5

Thank you, Sorro, for the suggestions.
I will give it a try, and hopefully, it will help.