Pumps, valves, probes, fittings, tubing and sensing components for precise sample preparation, reagent handling and instrument fluidics.
Syringe Pumps for Automated Dilution and Standard Preparation
Application guide · Automated dilution
Automated dilution should be designed from the smallest stock-solution aliquot and the final analytical matrix. Separate stock, diluent, carrier, blank and rinse functions so that a nominal dilution factor does not hide carryover, wrong acid strength or incomplete mixing.
Engineering example: a 100-fold, 1.00 mL preparation uses 10 μL stock plus 990 μL diluent. If the stock channel delivers 10.2 μL while the diluent remains 990 μL and mixing is complete, the concentration is about 1.98% above the intended value. This sensitivity explains why the small stock channel is selected first.[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
Fixed sample dilution
Actual stock aliquot, final volume and matrix
Keep stock and diluent errors separate
Calibration levels
Stock concentration, level sequence, blanks and replicates
Control high-to-low memory and traceable preparation order
Overrange re-dilution
Trigger rule, maximum factor and report linkage
Restore the flow path before accepting the repeat result
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
Stock channel
Final volume ÷ dilution factor
Select useful syringe stroke around the smallest aliquot
Diluent channel
Final volume − stock aliquot
Allow mixing and transfer volume
Matrix effect
Acid/salt/organic content after dilution
Volume ratio alone does not prove analytical equivalence
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
Initialize and prime→Select blank or stock→Meter stock aliquot→Meter diluent/carrier→Mix and transfer→Flush before next level
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
Correct volumes, wrong recovery
Matrix mismatch or incomplete mixing
Check final composition and mixing time
High standards affect low levels
Common-path memory
Reduce shared volume or add targeted rinse
Overrange repeat remains high
Trigger, factor or source-selection error
Audit software record and physical valve state
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
Prepared concentration
Independent standard or suitable analytical check
All calibration levels and re-dilution factors
Blank
Complete flow-path blank
Below the method-defined contribution
Traceability
Log stock, factor, valve state and repeat linkage
Result can be reconstructed from the liquid program
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.
