What do these products do in this instrument?
Syringe Pumps: Aspiration, Dispensing and Proportion-Based Preparation
Aspirate and dispense samples, standards or reagents in syringe-driven configurations, coordinated with valves and mixing. Record actual delivery from each path, reaction sequence and arrival time together.
HLD and HMD organize aspiration/dispensing paths with rotary and solenoid valves respectively. Capacity budgets include useful volume, holding stages and replenishment points; valve states and pump actions together create each delivery.
Organize syringe metering around aspiration, holding and dispensing
Syringe drives use controlled displacement for aspiration, holding and dispensing. With direct contact, source liquid enters the metering chamber; with system-liquid drive, sample can remain at the probe tip or a designated tube segment. Define wetted coverage before capacity, cleaning and replenishment. For repeated dispensing, track current inventory, delivered volume and next replenishment time.
Map valve connections to every action
Check port connections, opening/closing sequence and power-off state separately for rotary- and solenoid-valve configurations. Changing source does not automatically remove old liquid from the chamber or shared tubing. Plan flushing for formulation and residue requirements, then evaluate the first dose after switching and dose-to-dose variation.
Translate actual branch conditions into configuration requirements
| Condition | To confirm |
|---|---|
| Stored volume and timing | Define volume per operation, consecutive dispensing count, holding time and permitted replenishment window. |
| Valve positions and destinations | Provide a source, receiver and waste port diagram with open/closed and power-off states. |
| Liquid changes and first dose | Check shared residue, priming destination and actual received volume after standby or source changes. |
| Operation | Specific operating conditions |
|---|---|
| Sample metering | Actual sample volume, remaining source volume, probe-tip height, aspiration/dispensing speed and system liquid |
| Metered reagent addition and reaction timing | Working volume, addition order, liquid-arrival delay, mixing wait and detection trigger |
Compare product configurations by the roles on this page
| Product | Configuration option | Conditions to verify |
|---|---|---|
| HLD rotary-valve syringe pump | Aspiration, holding and dispensing with a rotary valve | Check source/outlet valve positions, capacity budget and replenishment timing |
| HMD solenoid-valve syringe pump | Metered aspiration and dispensing with solenoid valves | Check open/closed and power-off states, working volume and replenishment cycle |
Related operations and architecture comparisons
Sample metering
Include particles, salinity and matrix variation in the water-sample requirements. Validate metering at the analytical unit's receiver, separately from field-sample refresh time.
Metered reagent addition and reaction timing
Adding the same volume at different times can change a reaction. Record each actual delivery, mixing, temperature control and measurement time, then assess the reaction result.
Confirm product roles in actual operation
| Operation | Measurements and observations | Priority checks |
|---|---|---|
| Sample metering | Measure actual delivery at the receiver, covering routine small volumes and maximum task volume, first dose after idle, sample changes and high/low concentration sequences | Air aspiration, clots/particles, probe contact with a wall or leakage alter actual delivery |
| Metered reagent addition and reaction timing | Measure volume, actual arrival time and complete-reaction results together | Mismatch between liquid arrival and control trigger, residual droplets or inadequate mixing may alter reaction initiation |
Assess dose, reaction, blanks and recovery according to the method, and verify what is measured after filtration.
For repeated dispensing from one chamber, is checking total volume enough?
Measure each received dose, especially the first and last. Even when total volume is near target, individual errors may differ. Relate replenishment, valve switching and receiving actions to each result.
Validate field representativeness and internal metering separately. Filtration intended to protect components must still meet method requirements.