# How can I set micropipette volume with decimal separators, for example 109.5 in p200?

And how can I set:

• 150.1 in p200
• 871.3 in p1000
• 840.5 in p1000?
• What is the brand and model of your pipet? Jan 17 '19 at 6:51

It doesn't make sense to set volumes of decimals of microliters with a P200, since usually the accuracy of these pipettes is in the order of a few microliters. So even if you set your pipette at 190 uL, you may still dispense a volume ranging from 187 to 193 uL. For a P1000, due to higher volumes the inaccuracy is of course higher, usually +/- 10 uL or more. Some brands are more accurate than others, like Eppendorf or Finnpipette. I suggest you check the specs of your pipettes and see how much accuracy you can achieve.

• I think a fair take-home message here is you shouldn't, and with many brands you often can't. Rainin and Eppendorf P1000's measure to four places from 0100 to 1000, for example. The best bet is to use two different pipets, and use them in that fashion throughout the process to maintain consistency.
– CKM
Jan 14 '19 at 21:10

I would always use multiple pipetters in cases like that, but really the answer is that no pipetter is going to give you 4 sig figs of accuracy. It's just not possible with the technology.

For p200 the smallest unit is the tenth of a ul (0.1) but the intervals go by 0.2 so to set 109.5 (assuming your pipette can be adjusted between intervals) you need to set the pipette so the pointer is equidistant from the 109.4 and 109.6 mark. For the p1000 the smallest unit is 1 ul so you cannot set it to 871.3.

• Some brands of pipeters "click" at each allowed increment, so you won't be able to go between them. Jan 14 '19 at 23:10
• Interesting. Thanks for sharing I didn't know that.
– Cell
Jan 15 '19 at 1:53