16 mL Test Tubes, Round Bottom, PS, Natural — 222-2095-05I | 1/Bag | Caplugs® Evergreen

16 mL Round Bottom Test Tubes with Two-Position Snap Caps — PS, Natural, Sterile (222-2095-05I)

These 16 mL polystyrene round bottom test tubes measure 17 × 100 mm and ship individually packed to maintain sterility from receipt through point-of-use. Each tube includes a two-position snap cap that switches between a vented configuration for gas exchange during incubation and a sealed configuration for containment during transport or centrifugation. The round bottom geometry concentrates cell pellets and precipitates at the tube base, making resuspension and aspiration after centrifugation fast and efficient.

Technical Specifications

Applications

• Flow Cytometry & FACS: The round bottom PS format is the standard geometry for flow cytometry sample tubes; PS optical clarity is compatible with common fluorescent dyes and stains.
• Immunofluorescence & Cell Sorting: PS construction provides the optical transparency needed for sample inspection, staining protocols, and sorted-cell collection.
• Cell Pelleting & Resuspension: The round bottom concentrates pellets at a single point after centrifugation, minimizing sample loss during aspiration and resuspension steps.
• Hematology Sample Preparation: The 17 × 100 mm dimension suits standard hematology prep workflows requiring a 16 mL working volume.
• Serological Testing & Agglutination Assays: The round bottom format permits reading of agglutination patterns without the interference of a flat or conical base.
• Specimen Collection & General Sample Handling: Individual sterile packaging makes these tubes suitable wherever contamination control from tube to point-of-use is required.

Chemical Resistance

Quality & Procurement

Made in USA at Caplugs® Evergreen ISO-certified manufacturing facilities, these tubes are produced from virgin-grade, BPA-free, phthalate-free polystyrene resin. Lot-level quality controls enforce consistent tube geometry, wall thickness, and dimensional uniformity — critical for reproducible centrifugation and instrument-based assays in CAP, CLIA, and ISO 15189 regulated environments. LabSupplies.com is an authorized Caplugs® Evergreen dealer and ships from domestic inventory, with tiered volume pricing available for high-throughput clinical and research laboratories.

Frequently Asked Questions

Are these tubes sterile, and how is sterility maintained?
Yes — each tube is individually packed and sealed at the factory. The packaging maintains sterility from manufacturing through point-of-use, making them suitable for cell culture, specimen collection, and other contamination-sensitive workflows without the need for further processing before use.

What does the two-position snap cap do?
The snap cap has two distinct locking positions: a vented position that allows gas exchange during incubation steps, and a fully sealed position that provides containment during centrifugation, transport, or storage. Switching between positions requires no tools and can be done with one hand.

Are these tubes compatible with flow cytometers and FACS instruments?
The 17 × 100 mm round bottom PS format is widely recognized as the standard tube geometry for flow cytometry and FACS sample introduction. The natural PS construction provides the optical clarity required for fluorescence-based assays. Always verify tube outer diameter and length tolerances against your specific instrument's sample introduction specifications.

Can polystyrene tubes be autoclaved or used with organic solvents?
No — polystyrene is not autoclavable and will deform under high heat. It is also not compatible with acetone, aromatic solvents, or high concentrations of alcohols. These tubes are intended for aqueous buffers, dilute acids and bases, and short-term contact with lower-concentration alcohols such as methanol and isopropanol.