Achieving direct liquid contact between STAR pipette plunger and aspirated liquid

Pipetting without an air gap between the pipette plunger and the dispensed liquid is a fun, mildly destructive way to achieve more consistent flow-rates for precision applications.

Has anyone successfully done this on a STAR pipette? I imagine it could be possible to overaspirate via firmware commands - I thought to ask here as I start messing around with this myself.

To be clear, this will likely destroy your pipettes - do not try this at home!

This will 100% destroy the internal seals, the internal pressure sensor, and is overall a terrible idea. This mechanism wasn’t designed to be used in this way. There are plenty of other comparatively inexpensive liquid displacement systems including Hamilton’s own syringe pump systems available to do this. Some of which can be purchased on Ebay.

If you really want to destroy a $2500 piece of liquid handling technology that you own… I Say “have at it!”

In addition to this you can still buy used Hamilton 4000 units that do liquid displacement using syringe pumps. I’ve also seen a few AT+ units which use positive displacement that would also likely work for you. I don’t think they are making tips for the AT+ anymore though.


The issue with syringe pumps is let’s say you would like to array 100 different liquids. You’d need a whole exchanger valve setup to fill those 100 arrayed liquids into a syringe pump serially, or 100 syringe pumps all pre-loaded and pre-chilled in parallel.

Whereas I have 56 STAR pipettes laying around just waiting to eat oil. With just one pipette, I can array my 100 different conditions into a microfluidic setup using the same liquid handling steps we so are familiar with.

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I see what you are looking for. There is an “always there” air gap between the tip of the pipetting module and the plunger. This will be very difficult to “fill” as you are describing and would be very difficult to eliminate the air gap altogether.

It certainly could be possible to design something better suited to the task and specific application.