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measure many small volumes - (Feb/04/2011 )

Hi all. I have a tedious problem I hope you can help me with. I am doing a assay where I have to measure many small volumes
in the range 480ul to 520 ul. I have previously done this with a pipette, but it takes time and is not very accurate. If I remeasure it can differ
quite a lot (4-5ul). Aside from that, the main issue is time, it takes me 30 minutes of pipetting up and down.

I would rather avoid doing it by weight, contains cells of different size. I am aware of the irony, since it would also influence volume.
Even if it could be calculated by better methods, this is the way we do it. You know "This is the way it's always been done, case closed".

I have found a 1ml pipette with markings for each 10ul. But I want 2ul accuracy if possible. Anyone have a clever idea, or a product I didn't find? Oh, must be sterile, or at least sterile-ish.

Thank you, and have a nice weekend.


a 5 ul difference with 500 ul pipette is 1% that is pretty accurate. ~~ 500 ul is not considered a 'small volume'. If you were talking nl that would be very small and require specialized instrumentation. All I can suggest is make sure the pipette is calibrated and follow the instructions that came with the pipettor.


repeating pipette with a syringe, or a self-filling syringe dispenser like we use for medium. A link to a paper on this:My link.

-lab rat-

Perhaps I did not phrase myself correctly. English is not my native language. The volumes are unknown to me, and I have to measure them.
But, a syringe might actually be a good idea. I can remove a fixed volume with a pipette, and draw the rest with a fine syringe and read the value.


I see--I had assumed that you were measuring many small volumes to put into something, like for a large bacterial culture experiment.

In your case, the syringe type to use is a Hamilton syringe. These are glass syringes in a variety of volumes. They are expensive (~$30 usd each) the plunger is bent easily if you get too rough. They are autoclavable.

Good luck!

-lab rat-