Pumps, valves, probes, fittings, tubing and sensing components for precise sample preparation, reagent handling and instrument fluidics.
Pipetting Pumps for Automated Sample Preparation
Application guide · Sample preparation
Automated sample preparation often alternates between adding liquid and removing supernatant while leaving pellets, beads, membranes or other solid phases undisturbed. The pipetting channel must therefore control position and residual volume as carefully as nominal transfer volume.
Engineering example: after magnetic separation, removing 180 μL from a 200 μL well while leaving at least 15 μL above the bead pellet gives only 5 μL geometric margin before bottom tolerance and meniscus variation. The aspiration height and plate flatness may dominate the pump command.[1][2]
01Define the liquid, receiver and complete duty before selecting the component
Translate the analytical task into an engineering duty
Use case
Inputs to define
Decision supported
Supernatant removal
Solid-phase location, allowed residual and aspiration side
Protect the retained pellet or beads
Wash addition
Jet location, shear limit and resuspension requirement
Separate gentle overlay from deliberate resuspension
Elution recovery
Small final volume and required recovered analyte
Use low-retention tip and defined mixing
02Calculate the working point and the margin the instrument really needs
Calculations to complete before prototype selection
Quantity
How to define it
Why it matters
Removal target
initial volume − protected residual
Cannot exceed geometry-safe aspiration
Tip reach
deck height + vessel depth + clearance
Defines Z travel and collision margin
Workflow capacity
steps × samples × tips
Defines waste, tip storage and run time
Use minimum, routine and maximum conditions rather than one nominal point. Include the first cycle after priming or idle, the lowest source level, the highest expected restriction and the actual receiving geometry. A nominal capacity, free-flow value or theoretical command increment is not an acceptance result.
03Map the task to a FOREACH configuration and the rest of the fluid path
04Program the full liquid cycle, including prime, wash and recovery
Locate vessel and solid phase→Pick correct tip→Aspirate or add at taught height→Mix only when required→Transfer to next vessel→Eject tip and log step
A complete method cycle is more than the active delivery step
The exact physical order and parallel actions depend on the instrument. Retain each state in the control and verification plan.
Record valve states, motion, dwell, sensor windows and rejected recovery cycles. This makes throughput and liquid consumption auditable and prevents a fast component movement from being reported as the complete analyzer cycle.
05Design abnormal-state diagnosis before the fault occurs
Observed result, likely mechanism and useful next action
Observed condition
Likely mechanism
Engineering response
Pellet loss
Aspiration too deep/fast or pellet displaced
Raise/offset aspiration and reduce flow
High residual variability
Plate geometry or liquid film
Use calibrated height and alternative aspiration pattern
Clogged tip
Particles or precipitate
Use wider tip or upstream preparation change
The controller should distinguish a recoverable event from a result-invalidating event. A retry is useful only after the original cause has been removed and the liquid path has returned to a verified state.
06Accept performance where the liquid is actually used
Minimum qualification plan for the integrated channel
Result
Where or how to measure
Acceptance question
Residual volume
Measure across vessel positions and lots
Protects downstream concentration
Analyte recovery
Compare automated and reference preparation
Demonstrates useful recovery, not motion alone
Cross-contamination
High-to-blank sequence
Meets workflow threshold with tip policy
Test the exact liquid and complete wetted path at minimum, routine and maximum conditions.
Separate first-cycle, steady-state and post-idle results; do not average away recovery behavior.
Challenge the relevant fault and confirm the controller prevents an invalid result from being accepted.
Retain the configuration, software sequence, consumables and receiving-position result together as the qualification record.
