8.0 mL Round-Bottom Sterile Test Tubes with Two-Position Snap Cap — PS, 13 × 100 mm, 25/Bag Unassembled (222-2061-050)
These 8.0 mL polystyrene round-bottom test tubes measure 13 × 100 mm and are supplied sterile in 25/Bag unassembled format for larger-volume serology, microbiology culture, blood bank processing, and flow cytometry workflows. Each tube ships with a two-position snap cap in the same bag — clicking to a vented position for gas exchange during incubation or centrifugation, or to a fully closed position for sealed storage and transport — allowing labs to assemble only what they need and reducing per-unit cost versus individually pre-assembled options. The optical clarity and low autofluorescence of polystyrene make these tubes particularly well suited to direct visual agglutination reading and fluorescence-based cell analysis.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (MPN) | 222-2061-050 |
| Capacity | 8.0 mL |
| Dimensions | 13 × 100 mm |
| Geometry | Round Bottom |
| Material | Polystyrene (PS) |
| Color | Natural (clear) |
| Cap / Closure | Two-position snap cap — vented and fully closed; ships unassembled |
| Sterility | Sterile |
| Pack Size | 25/Bag, Unassembled |
| BPA / Phthalate / Latex | BPA-Free, Phthalate-Free, Latex-Free |
| Country of Origin | USA |
Applications
- Tube serology: The 8.0 mL capacity and optical clarity of PS allow direct visual reading of agglutination reactions — button, partial agglutinate, or dispersed cell patterns — against the clear tube wall in 13 × 100 mm racks.
- Blood bank processing: Eluate preparation and larger-volume crossmatch procedures that require more capacity than the standard 12 × 75 mm format.
- Microbiology culture: Liquid broth culture in 13 × 100 mm rotor or rack positions; snap cap vents during aerobic incubation and seals for transport or storage.
- Flow cytometry sample prep: The low autofluorescence background of PS reduces interference during fluorescence-based cell detection and sorting.
- Clinical centrifugation: Round-bottom geometry suits centrifuge rotors configured for 13 × 100 mm tubes — verify adapter compatibility with your specific rotor.
- Sample collection and storage: Sterile construction and a re-sealable snap cap make these suitable for 8.0 mL serum, plasma, or other specimen collection and short-term storage.
- Serology reagent preparation: The larger 8.0 mL volume accommodates bulk reagent dilutions for high-throughput serology operations.
Chemical Resistance
| Reagent / Condition | Compatibility |
|---|---|
| Aqueous buffers / saline (pH 4–10) | Excellent |
| Dilute acids and dilute bases | Good — short-term contact at typical lab concentrations |
| Serum, plasma, whole blood | Excellent |
| Ethanol > 70% / isopropanol | Not recommended — PS degrades with prolonged contact |
| Acetone | Not compatible — will craze or dissolve PS |
| Chloroform / aromatic solvents | Not compatible |
| Autoclaving / dry heat sterilization | Not recommended — PS is not autoclavable |
Quality & Procurement
Made in USA, these Caplugs® Evergreen test tubes are manufactured from BPA-free, phthalate-free, and latex-free polystyrene resin under ISO 9001 quality management. Sterile pack integrity supports direct use in clinical and regulated research environments without additional decontamination steps. LabSupplies.com is an authorized Caplugs® Evergreen dealer shipping from USA inventory, typically same business day for stocking items, with tiered volume pricing available for clinical labs, hospitals, blood banks, and grant-funded research programs.
Frequently Asked Questions
What does "unassembled" mean — are the caps included?
Yes, the snap caps are included in the bag with the tubes, but they are not pre-mated to each tube. Lab staff assemble each tube before use by pressing the cap onto the tube. This format is standard for high-volume clinical serology and culture labs where bulk assembly is preferred over individually pre-assembled, higher-cost options.
Can the snap cap be vented during centrifugation?
Position 1 of the two-position snap cap provides a vented, partially open closure designed to allow gas exchange during incubation, aerobic culture, or centrifugation. Position 2 clicks to a fully closed, sealed position for storage, transport, and aerosol containment. Always verify that your centrifuge rotor and protocol permit the use of vented closures before centrifuging.
Why use polystyrene rather than polypropylene for these tubes?
Polystyrene offers superior optical clarity and lower autofluorescence compared to polypropylene, which are critical properties for reading agglutination reactions visually in tube serology and for minimizing background signal in fluorescence-based flow cytometry applications. For workflows requiring autoclaving or extended contact with alcohols or organic solvents, polypropylene would be the appropriate choice instead.
Are these tubes compatible with standard 13 × 100 mm tube racks and centrifuge rotors?
The 13 × 100 mm outer dimensions fit standard 13 mm tube rack positions used in serology and blood bank labs. For centrifugation, the round-bottom geometry is suited to rotor positions designed for this tube format, but rotor adapter compatibility should always be verified against your specific centrifuge model and speed requirements before use.