Micropipetting
Introduction to Micropipetting
Micropipettes allow for simplified working when dispensing smaller volumes in the microlitre range (μL; 10⁻⁶ L). Micropipettes are available in a range of sizes, and the pipettors are usually referred to by the upper capacity. For example. a 'P1000' pipette refers to 1000 μL (1 mL), which usually has a working range of 200 -1000 μL. Micropipettes offer easy adjustment in order to dispense any volume within their operating range with reasonable accuracy. This is usually achieved by altering a numeric dial at the end of the pipette, with the volume being displayed on the number dial.
Micropipettors are most amenable to use with aqueous solutions, which is why their use is widespread in biological sciences. More information on their suitability can be found in the 'When to use' tab.
Volumes
A range of micropipettes are readily available commercially, with the smallest usually being P2 all the way up to a P10000 (10 mL) pipettor. Within the range, there is overlap with the volumes which can be dispensed, for example a P200 may take volumes from 20 – 200 uL, and a P1000 pipette may range from 200 – 1000 uL. Generally, a smaller pipette offers better accuracy to measure the same volume. The most abundant pipettors tend to be the P1000 and P200 micropipettes. The table below gives typical values for a range of micropipettes (table based on Labnet BioPette™ Plus Single-Channel Pipettors).
Name
Volume range / μL
Accurancy /%
Precision /%
Tips required
P2
0.1-2
±40.0 to ±1.5
≤12.0 to ≤0.7
10
P10
0.5-10
±4.0 to ±0.5
≤2.8 to ≤0.4
10
P20
2-20
±3.0 to ±0.8
≤1.5 to ≤0.3
200
P100
10-100
±1.6 to ±0.6
≤0.8 to ≤0.2
200
P200
20-200
±1.2 to ±0.6
≤0.6 to ≤0.2
200
P1000
100-1000
±1.6 to ±0.6
≤0.4 to ≤0.15
1000
P5000
1000-5000
±0.6 to ±0.5
≤0.25 to ≤0.15
5000
P10000
1000-10000
±2.5 to ±0.5
≤0.6 to ≤0.2
10000
Pipette tips
The variation in pipette size requires a range of specific tips to be available. The tips are usually made of plastic which are disposed of after use. It is important to use the right tip size for the pipettor. Too large results in reduced accuracy, whereas if you use a pipette tip that is too small for the volume then it will reach the pipette barrel, causing contamination and potentially damaging the pipette.
Teaching Labs
In the teaching labs the main pipettor model is a P 1000 BioPette™ single-channel pipettor.
