What do these products do in this instrument?
Piston pumps: fixed-probe sample and reagent metering
Drive samples or reagents into reaction vessels in fixed-probe metering architectures. Coordinate probe motion and cleaning, distinguishing actual added volume, tip droplets and between-sample carryover.
EA, SM and TM provide options for comparing capacity, wetted configurations and installation space. Verify actual doses from working stroke and the complete wetted path; check system-liquid drive and direct sample contact with the pump head separately.
Distinguish piston displacement from actual received volume
Piston pumps use controlled displacement for discrete aspiration and dispensing. Sample may enter the head directly or remain at the probe tip while system liquid transmits displacement; wetted coverage, priming and cleaning differ. Map aspiration, holding, dispensing and replenishment paths first, then relate stroke to probe-tip delivery.
Further technical reading
Combine metering, valve positions and container actions into a complete cycle
Delivery requires coordination of metering drive, source switching and receiving-end actions. Usable capacity must cover working volume and other cycle displacements, with replenishment in permitted windows. Check tip droplets, bubbles and shared residual liquid through the complete path; remeasure received volume after changing pump heads, tubing lengths or interfaces.
Translate actual branch conditions into configuration requirements
| Condition | To confirm |
|---|---|
| Working stroke | Set working sample or reagent doses for the fixed-probe architecture, including priming and replenishment displacement within the reaction schedule. |
| Liquid contact and pressure | Map the sample-contact or system-liquid path, probe interface and pressure states; identify surfaces included in the probe-wash sequence. |
| Delivery and recovery | Compare received volume and probe droplets through aspiration, delivery and washing, including the next container after a concentrated sample. |
| Operation | Specific operating conditions |
|---|---|
| Sample addition with a fixed probe | Method-permitted sample, working dose, source level, fixed-probe geometry, liquid-contact architecture and the complete sampling/washing sequence |
Compare product configurations by the roles on this page
| Product | Configuration option | Conditions to verify |
|---|---|---|
| EA standard piston pump | Finite-stroke metering | Compare configurations by routine dose, total cycle displacement and wetted materials |
| SM miniature piston pump | Discrete metering in compact installations | Check installation space first, then validate working doses and actual accuracy |
| TM ultra-miniature piston pump | Discrete metering in limited space | Check installation space and configuration before measuring actual delivery; an ultra-miniature design does not imply a smaller reliable dose |
Explore specific operating and validation tasks
Sample addition with a fixed probe
Sample-volume error affects reaction ratios, while external probe droplets may contaminate the next container. Combine aspiration, delivery and probe washing into a complete sequence and compare recovery after concentrated samples.
Confirm product roles in actual operation
| Operation | Measurements and observations | Priority checks |
|---|---|---|
| Sample addition with a fixed probe | Measure sample received in the reaction vessel, then assess carryover through the fixed-probe wash sequence. Check first delivery after idle and recovery after concentrated samples. | Air aspiration, leakage, probe-wall contact or retained droplets can affect received volume and contaminate the next container; investigate dose error and carryover separately. |
Verify actual sample or reagent addition through the fixed probe and assess carryover after washing with the assay. Magnetic capture and bead-wash performance belong to the separate washing operation.
Are piston pumps of equal capacity directly interchangeable?
Also check wetted materials, interfaces, mounting, drive and pressure conditions. After replacement, recheck delivery, cleaning and first-dose recovery with the original sequence and actual liquids. Capacity is only one comparison criterion.
Pump flow alone does not prove adequate washing; validate magnetic capture, mixing and aspiration position across the whole station.
References
View references (4)
- [1]FOREACH EA standard piston pump: configurations and specifications
- [2]FOREACH SM miniature piston pump: configurations and specifications
- [3]FOREACH TM ultra-miniature piston pump: configurations and specifications
- [4]Beckman Coulter Access: an assay example of magnetic solid-phase separation, washing and substrate detection