Tips on Pipette

The working principle of pipette is divided into two types: internal piston type and external piston type:
The built-in piston uses the air pressure difference to replace the same volume of air with the target liquid through the movement of the piston inside the pipette. In this way, there is a long air column between the piston and the liquid, and there is a filter element in the middle, so the piston of the pipette is not polluted, and it is convenient to replace the suction head.
The external piston directly contacts the piston with the target liquid. When the piston is pulled up, the atmospheric pressure will squeeze the liquid into the suction head. In this way, there is no air gap between the piston and the liquid, and the air pressure is 0, which can avoid the internal and external pressure imbalance caused by liquid gas/vaporization, and can better deal with the liquid with poor liquidity. Such as stepper continuous liquid separator.
How to handle viscous liquid:
Small partners who do more experiments may often encounter the problem that the liquid transfer operation is always inaccurate due to the poor fluidity of viscous liquids such as glycerin.
Generally speaking, we recommend reducing the speed of liquid transfer, including suction and discharge, so that the air pressure can be fully balanced to achieve the desired volume of liquid transfer.
Rinsing the suction head can also make the inner wall of the suction head hang viscous reagent in advance, which is equivalent to eliminating the loss of hanging wall in advance, and can also improve the accuracy of liquid transfer.
In addition, we can also use the “reverse liquid transfer” operation, which is simply to press the second gear directly when aspirating, and only press the first gear when discharging, which can also improve the accuracy of liquid transfer of viscous liquid.
Of course, if conditions permit, we can also choose to use Stepper continuous liquid separator for liquid transfer. Its external piston principle can well avoid the difficulty of liquid transfer of viscous liquid.

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