50 mL Centrifuge Tube Screw Caps — HDPE, Lavender, 1000/Bag | Falcon® Compatible (300-3541-L20)
These lavender High-Density Polyethylene (HDPE) screw caps are designed for 50 mL centrifuge tubes and supplied in bulk 1000/Bag packaging for high-throughput clinical and research workflows. The lavender color mirrors the CLSI H3 lavender-top EDTA anticoagulant convention, making them ideal for color-coded routing of large-volume EDTA-preserved specimens such as molecular panels, HbA1c correlation studies, and DNA banking. Built for demanding environments, part number 300-3541-L20 delivers IATA P650-compliant leak-free closure, –80 °C cryogenic stability, and autoclave compatibility at 121 °C.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (MPN) | 300-3541-L20 |
| Cap Type | Screw cap — threaded engagement |
| Material | High-Density Polyethylene (HDPE) |
| Color | Lavender |
| Tube Compatibility | Caplugs® Evergreen 50 mL centrifuge tubes |
| Thread Note | 50 mL format only — larger than 300-3532 (20/30 mL) and 300-3010/300-3022 (15 mL) families; not interchangeable |
| IATA P650 | Compliant — leak-free primary container seal |
| Cryogenic Storage | Compatible to –80 °C |
| Autoclave Compatibility | 121 °C / 15 psi |
| Sterility | Non-Sterile |
| Pack Size | 1000/Bag |
| BPA / Phthalates | BPA-free; no phthalate plasticizers |
| Country of Origin | USA (California) |
Applications
- Large-volume specimen sealing: IATA P650-compliant closure for high-volume serum, plasma, and urine in 50 mL tube formats
- EDTA-preserved molecular specimens: Lavender color-coding supports visual routing of molecular panels, HbA1c correlation studies, and large-volume EDTA-preserved batches following CLSI H3 conventions
- DNA/RNA extraction prep: Replaces or supplements caps on 50 mL nucleic acid extraction tubes across high-volume workflows
- Genomics and biorepository banking: HDPE cryo stability at –80 °C makes these caps suitable for long-term large-volume DNA/RNA biobank archiving
- Centrifugation (capped): Secure screw-thread engagement retains the cap through centrifuge forces during sample separation
- Cell culture harvest: HDPE is compatible with common culture media formulations used in 50 mL tube harvest workflows
- Color-coded batch routing: Available in nine colors across the 300-3541 range, covering primary clinical specimen-type routing conventions
Compatibility
These caps are designed to fit Caplugs® Evergreen 50 mL centrifuge tubes and are compatible with Falcon®-format 50 mL centrifuge tubes sharing the same neck thread geometry. The 300-3541 thread specification is unique to the 50 mL format and is distinctly larger than both the 300-3532 family (20/30 mL tubes) and the 300-3010/300-3022 family (15 mL tubes) — the three cap families are not interchangeable. Validate cap-to-tube thread fit with a sample quantity before committing to a bulk purchase, particularly when replacing caps on tubes from other manufacturers.
Chemical Resistance
| Reagent / Condition | Compatibility |
|---|---|
| Aqueous buffers / saline | Excellent |
| Dilute acids and bases | Excellent |
| Alcohols (ethanol, isopropanol) | Good — suitable for most lab concentrations |
| Many organic solvents (esters, ketones at low concentration) | Good — verify with specific reagent before extended contact |
| Chlorinated solvents (chloroform, methylene chloride) | Not recommended |
| Aromatic solvents (toluene, xylene) | Not recommended |
| Cryogenic storage (–80 °C) | Compatible |
| Autoclave (121 °C / 15 psi) | Compatible |
Quality & Procurement
Made in USA, these Caplugs® Evergreen centrifuge tube caps are manufactured in California from BPA-free, phthalate-free HDPE resin under ISO 9001 quality management. The HDPE formulation meets the requirements for IATA P650 leak-proof primary container closures, supporting compliant specimen transport. LabSupplies.com is an authorized dealer of Caplugs® Evergreen consumables and ships from USA inventory, with tiered pricing available for high-volume institutional, clinical, and grant-funded laboratory purchasers.
Frequently Asked Questions
Will these caps fit my existing 50 mL Falcon® tubes?
These caps are designed for Caplugs® Evergreen 50 mL centrifuge tubes and are compatible with Falcon®-format tubes sharing the same 50 mL neck thread geometry. Because thread dimensions can vary by manufacturer and tube generation, we strongly recommend verifying fit with a sample before placing a bulk order.
Can these caps be used at –80 °C for long-term biobanking?
Yes — HDPE maintains its structural integrity and thread seal at ultra-low temperatures down to –80 °C, making these caps suitable for cryogenic biorepository storage of large-volume specimens and nucleic acid archives.
Are these caps autoclavable?
Yes — HDPE is autoclavable at 121 °C / 15 psi, allowing sterilization of capped tubes before use in sterility-sensitive workflows such as cell culture.
Why are these caps lavender, and are other colors available?
Lavender mirrors the CLSI H3 lavender-top EDTA anticoagulant tube convention, providing intuitive color-coded routing for EDTA-preserved molecular specimens in 50 mL formats. The 300-3541 range is available in nine colors — including natural, blue, orange, and green — all sharing the same HDPE thread specification so labs can standardize on a single cap family across multiple specimen types.