It is recommended to have a pipette with an external piston if you need to piptette special samples frequently in order to assure the accuracy. For occasionally pipetting of special samples, here are some tips.
Pipetting volatile samples
- Be sure to rinse twice before pipetting;
- Drain the liquid as soon as possible after the suction is completed.
Pipetting high viscosity samples
Use reverse pipetting mode: press the aspiration/discharge button to the second gear (second stop point) when aspirating liquid, and press the button to first gear (first stop point) when discharging liquid. In addition, a residence time of 3-5 seconds is required during both suction and discharge.
Pipetting high-density/low-density samples
The accuracy values of the pipette are based on transferring pure water. If the density of the sample is very different from the density of water, the accuracy will be correspondingly different. Therefore, you need to know the density of the sample before pipetting, and then adjust the measuring range to the product of the volume and density of the sample to be transferred.
For example, if the density of a sample is 1.2g/cm3 and you need to transfer 300μL, then you should set the measuring range to 360μL. This is only a rough adjustment method. A strict adjustment method also requires the use of a measure or a scale as an auxiliary tool for accurate calculations.
Pipetting high/low temperature samples
- Never rinse the tip before pipetting;
- Use a new tip every time you pipet;
- The suction and discharge of liquid must be completed as soon as possible.