Locate the source, drive and receiving position for this task
Define actual sample, diluent or internal-standard volumes, concentration at each stage, mixing and subsequent sampling conditions. Follow the diagram to confirm liquid contact, pressure and destination at each position before assigning drive and connection roles.
Establish dilution ratios from actual delivered volumes
List sample volume, diluent volume and total received volume first. For serial dilution, also record the volume remaining at each stage and the next aliquot. Calculate capacity, refills and final recovery together. A small sample fraction often requires more attention to working stroke than the larger diluent volume.
| Condition to compare | Information required | Selection affected |
|---|---|---|
| Preparation ratio | Sample volume, diluent volume and final total volume | Account for actual delivery from both paths separately |
| Usable mixed solution | Mixing action, minimum liquid level and subsequent aliquot volume | Define vessel and sampling position |
| Method conditions | Dilution matrix, allowable holding time and result calculation | Check dilution and reporting rules against the method |
Compare product options against task requirements
The following candidate options match this page's responsibilities. Compare them against the operating conditions described, then check capacity, materials and interfaces on the product pages. Card images show representative configurations; suitability must still be confirmed at actual operating points and by application results.
| Product category | Corresponding role | Confirm before selection |
|---|---|---|
| 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 |
| MRV3 multiport rotary valve | Multiple-source selection | Compare 10-, 16- and 24-port options and port diagrams; verify high-pressure suitability separately |
Maintain sample identity through delivery, mixing and repeat processing
Confirm sources by sample identity, deliver in sequence and mix for the vessel used. Displace shared channels first. When changing ratios or repeating an over-range sample, retain the previous cycle's delivery status to avoid mistaking a diluted sample for the original.
Action records should link commands, valve or interface states and actual received results. When raw material, container or sample identity changes, reconfirm shared paths and conditions permitting the next step. Completion of drive movement alone does not replace task acceptance.
Validate complete dilution using ratios and method response
Measure each liquid's actual volume first, then assess mixing using ratio checks, standards or spikes. Cover minimum original-sample volume, maximum dilution, sample changes and first doses. Distinguish volume error, residue and insufficient mixing.
| Validation scenario | Measurement or observation | Interpretation and action |
|---|---|---|
| Ratio and uniformity | Measure both liquid volumes and mixed concentration separately | If volume is stable but concentration varies, check mixing and interfaces |
| Subsequent small doses | Compare initial sampling and secondary sampling at low remaining volume | Separate subsequent sampling error from the original preparation error |
Record test medium, configuration, installed path and operating sequence; present routine operating points and boundary results separately. Calculations support design discussions, component documentation checks models, and installed measurements confirm the actual task.
After an abnormality or maintenance, first identify which segment needs recovery
Small-volume error, shared-path residue or insufficient mixing can change the actual ratio. Check results from the affected step before resuming the next action.
Retain current source, container identity, completed actions, valve or interface state and actual receiving information. Use the table to locate the stage that changed before deciding to retry, continue or restart. After recovery, recheck the relevant operating point before returning an uncertain action to the automatic cycle.
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References
View references (10)
- [1]Roche — Glucose HK Gen.3, cobas c 303 / c 503 / c 703, V7.0 (2024)
- [2]FOREACH — EA Piston Pump Datasheet, basic capacities and test conditions
- [3]FOREACH — EA-100-PEEK configuration and specifications
- [4]CDC / NHANES — Sodium, Roche Cobas 8000 Laboratory Procedure Manual (2021–2023)
- [5]Hortin et al. — Problematic Proteins: A Patient with a High Paraprotein Concentration (2024)
- [6]FOREACH — Piston-pump head and wetted-material selection
- [7]Hamilton — Microlab 600 Basic Manual, Rev. K
- [8]FOREACH — EAS Easy-to-Degas Piston Pump Datasheet
- [9]Albert and Bradshaw — Importance of Integrating a Volume Verification Method for Liquid Handlers: Applications in Learning Performance Behavior (2007)
- [10]Ouyang et al. — Strategies to Maintain Sample Integrity Using a Liquid-Filled Automated Liquid-Handling System with Fixed Pipetting Tips (2008)