Pumps, valves, probes, fittings, tubing and sensing components for precise sample preparation, reagent handling and instrument fluidics.
Mixing Paddles and Probes for Analytical Reactions
Application guide · Mixing
Mechanical mixing is selected from the vessel, liquid volume, viscosity, reaction time and shear sensitivity. The relevant result is compositional uniformity before the read window, not motor speed in isolation.
Engineering example: a 200 μL reaction volume that must be read 8 seconds after the final reagent addition leaves less than 8 seconds for probe withdrawal, mixing, settling and detector positioning. Mixing time must therefore be allocated from the complete instrument sequence.[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
Reaction mixing
Final volume, reagent order and reaction time
Reach uniformity before measurement
Resuspension
Pellet/bead strength and allowed shear
Recover material without splash or loss
Viscous working solution
Viscosity, temperature and air entrainment
Use geometry and speed that avoid a persistent vortex
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
Immersion
liquid height and bottom clearance
Avoids dry running or vessel contact
Mix time
time to defined uniformity
Must fit between addition and read
Wash demand
immersed area and retained film
Sets cleaning cycle and carryover risk
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
Add liquids→Move mixer to safe depth→Ramp to selected speed→Mix for validated time→Stop and settle→Withdraw, wash and read
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
Concentration gradient
Insufficient time or poor geometry
Use tracer mapping across the vessel
Bubbles or foam
Excess speed or shallow immersion
Lower speed/change geometry and allow release
Carryover
Retained film on mixer
Qualify full external wash
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
Uniformity
Tracer/analyte samples from defined positions
Meets method variation limit
Reaction timing
Uniformity achieved before read window
Supports required throughput
Sample integrity
Foam, shear and temperature check
No unacceptable method effect
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.
