This article explains how to troubleshoot viscous liquids
Highly viscous liquids can cause the pipetting system to behave differently than assumed by the controlling software. The software can adapt its behavior to work with highly viscous solutions by changing certain parameters within the liquid classes.
Aspiration
- Aspiration speed: highly viscous liquids may require lower aspiration speed. Aspiration speed could be reduced to 10 µl/s (eg. for 50% glycerol) or even to 5 µl/s (eg. for 87% glycerol).
- Delay after aspiration: when working with viscous samples implementing a delay of ≥ 500 ms is recommended. The delay could be increased to up to 2000 ms for highly viscous liquids (such as 87% glycerol).
- Retract speed: the recommended retract speed is 5 mm/s to prevent loss of liquids due to surface tension. Retracting the tip from the liquid too quickly can result in aspiration of air instead of liquid and may lead to droplets formation on the outside of the tips.
Dispense
To obtain optimal pipetting results, using the standard pipetting method (free dispense), the following settings are recommended:
- Dispense speed: highly viscous liquids may require a lower dispense speed and dispense in contact mode. Dispense speed could be decreased to 10 µl/s (eg. for 50% glycerol) or even to 5 µl/s (eg. for 87% glycerol).
- Delay after dispense: when working with viscous samples implementing a sufficiently long dispense delay of ≥ 200 ms is recommended. The delay could be increased to up to 1000 ms for highly viscous liquids.
- Retract speed: the recommended retract speed is 5 mm/s.
Further Recommendations
Depending on the viscosity of the liquids, it is recommended to adjust the airgap parameters:
- Recommended STAG (System Trailing Air Gap) is 8 µl/s (eg. for 50% glycerol) or even less – 5 µl/s for liquids of higher viscosity (eg. for 87% glycerol).
- Recommended LAG is 2 µl/s.
- Recommended TAG is 1 µl/s (could be 0 for highly viscous liquids such as 87 % glycerol).
- When multi-pipetting with Air LiHa you may need a slower acceleration speed
Further Help
For further help, please refer to our Helpdesk.
Link to Tecan Product Page:
401812-020