Pumps, valves, probes, fittings, tubing and sensing components for precise sample preparation, reagent handling and instrument fluidics.
Wash Probes and Stations for Carryover Control
Application guide · Probe washing
Reusable-probe washing must clean the internal liquid path and the external wetted surface within the available cycle time. Wash chemistry, volume, jet coverage, aspiration and soak time must be assigned to the contamination mechanism rather than increased indiscriminately.
Engineering example: supplying 3 mL internal wash and 5 mL external-station wash per cycle creates 8 mL liquid waste before aspirated air. At 60 cycles per hour, the wash source and waste system must handle at least 480 mL/h plus prime, recovery and service margins.[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
Internal wash
Probe bore, retained sample and wash compatibility
Exchange the complete internal path
External wash
Immersed length, splash and station geometry
Wet all sample-contact surfaces
High-risk sample recovery
Protein/lipid/clot contamination and allowed chemistry
Use a validated special wash or service sequence
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
Wash exchanges
wash delivered ÷ sample-contact path volume
Initial design value; verify carryover
Drain demand
liquid pulse + aspirated air/foam
Must exceed supply without overflow
Cycle budget
fill + contact + drain + probe motion
Determines whether normal and special wash fit
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
Enter wash station→Start drainage→Flush internal bore→Wash external surface→Allow drain and drip release→Check blank or resume sampling
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
Carryover remains
Wrong chemistry, volume or contact surface missed
Map contamination instead of only adding time
Station overflows
Drain lags wash pulse
Coordinate start and increase installed aspiration
Probe clogs
Deposit not removed by routine wash
Run defined recovery or service replacement
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
Carryover
Worst contaminated sample followed by blank
Meets assay limit
Residual liquid
Probe exterior and outlet after wash
No droplet transferred to next vessel
Waste capacity
Repeated maximum wash cycles
No overflow or liquid carryover into protected path
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.
