This article will guide you through different liquid detection modes present on Freedom EVO.
The Liquid Handling Arm (with sensors and associated electronics) can be used for three different functions related to the liquid detection systems:
- cLLD (capacitive Liquid Level Detection) – present in all Liquid Handling arms (Liquid LiHa and Air LiHa), used for LLD of conductive liquids.
- pLLD (pressure Liquid Level Detection) – liquid level detection mode used for LLD with non-conductive liquids. Available on all Air LiHa arms, available on Liquid LiHa arms if they are upgraded with the MultiSense option.
- PMP™ (Pressure Monitored Pipetting) – process control feature, allowing the arm to check the quality of the liquid transfer as it is pipetting. Available on all Air LiHa arms, available on Liquid LiHa arms if they are upgraded with the MultiSense option. This option requires additional software features to be enabled in order to use it.
Capacitance liquid level detection (cLLD)
Capacitance liquid level detection (cLLD) detects the liquid surface through a change of the electrical capacitance of the pipetting tip when the tip enters or exits the liquid. cLLD is carried out with the detection mode, liquid conductivity, detection speed and double distance settings which you specified on the Global dialog box for the liquid class.
The conductivity of the liquid and the labware type have influence on the detectability.
There are three conductivity options:
- Very good (Serum, DNA solution, buffer)
- Good (Tap water)
- Bad (DMSO, ethanol, distilled water)
Pressure liquid level detection (pLLD)
Pressure-based liquid level detection (pLLD) detects the liquid surface through a change of pressure in the airgap between the sample and the pressure sensor inside the tip adapter when the pipetting tip enters or exits the liquid.
Unlike cLLD, it can also detect non-conductive liquids.
pLLD is carried out with sensitivity and liquid characteristics.
- Sensitivity: depends on the liquid type, similar to cLLD conductivity.
- Liquid Characteristics: hydrophilic (often water-based, often conductive) or hydrophobic (often non-water-based, often non-conductive). If the settings listed as “often” here are not working as expected, try other options based on the liquid type, or contact the helpdesk for additional assistance.
Pressure Monitored Pipetting (PMP)
The PMP feature is designed and verified to monitor pressure changes during pipetting operations in order to detect potentially incorrect liquid transfers. PMP detects aspiration and dispense errors by comparing recorded and modelled (real-time-simulated) pipetting pressure signals. It can detect the quality of the aspirate or dispense, but not how much was transferred.
The PMP automatically adjusts the pressure curve profile to the user-defined parameters:
- Targeted aspirate and dispense volumes
- Sample viscosity
- Sample density Aspiration and dispense speeds
- Tip types
Only PMP liquid classes can be used for PMP to function. PMP liquid classes are either Default liquid classes with “PMP” in the name, or custom liquid classes generated directly from one of these default PMP liquid classes.
Please note: The PMP feature comes only with the MultiSense™ hardware option.
Further Help
For further help, please refer to our Helpdesk.
Link to Tecan Product Page:
401812-027