MUHWA 5mL Microcentrifuge Tubes — Round Bottom, Graduated, 300 pcs/Pack

MUHWA 5mL Microcentrifuge Tubes — Round Bottom, Graduated, 300/Pack

When a 2mL tube isn't enough but you don't want to break out the 15mL conical, that's where the 5mL round bottom tube fits. It handles the intermediate volumes that fall between microcentrifuge and conical tube territory — bacterial pellets from 3-5mL cultures, clarified lysate after centrifugation, or simply storing a working aliquot of enzyme or antibody at -20°C where you want more than a single-use volume.

The round bottom geometry matters at this size. After spinning down a bacterial pellet at 5,000 x g, the cells collect in a tight plug at the bottom center — easy to see, easy to decant the supernatant without disturbing the pellet. Compare this to a conical 5mL tube where the pellet smears along the angled wall and you end up pouring off cells with your spent media. The round bottom also distributes centrifugal stress evenly, so the tube wall doesn't develop stress cracks after repeated spins the way some thin-walled conical designs do.

Frosted writing area — label the tube, not the rack

Both the cap and the tube body have a frosted patch that takes permanent marker and ballpoint pen. Write your sample ID, date, or initials directly on the tube — no label tape that peels off in the -80°C freezer or smears when ethanol drips on it. The frosted surface holds ink through freeze-thaw cycles and brief solvent exposure. For labs that track samples by tube rather than by rack position, this eliminates the "which unlabeled tube was the positive control?" problem.

Cap design — snap shut, stay shut

The attached snap cap closes with a tactile and audible click. You feel it through your glove. Once sealed, the cap stays closed during a 30-minute incubation at 65°C, holds at -80°C without the plastic contracting enough to break the seal, and won't pop open during centrifugation within the rated g-force range. The thumb tab is sized for gloved hands — flick it open with one hand while your other hand holds the pipette. No two-handed wrestling with a stuck cap.

Graduated markings you can read

Molded-in volume marks at 1.0, 2.0, 3.0, 4.0, and 5.0mL. The graduations are raised into the plastic during molding, not printed on the surface — they survive ethanol sprays, autoclave cycles, and repeated handling without fading or washing off. Useful for quick volume estimation when you're collecting supernatant or checking that you've transferred the full volume after a spin.

Common applications

These 5mL tubes fit into daily workflows where mid-range volumes are the norm. Spin down bacterial pellets from 3-5mL overnight cultures in a benchtop centrifuge with swing-bucket or fixed-angle rotors. Clarify cell lysates after sonication or chemical lysis. Store aliquots of precious reagents at -20°C or -80°C — the 5mL volume is convenient for working stocks of restriction enzymes, polymerases, or antibodies that you'll use over several weeks. Collect supernatant fractions from protein precipitation or ammonium sulfate cuts. For clinical labs: urine or serum sample aliquoting and short-term storage.

Specifications

Centrifugation & handling notes

Always use a rotor or adapter that fully supports the tube wall. At g-forces above 8,000 x g, an unsupported 5mL tube wall can deform and potentially rupture. Most benchtop centrifuges with 15mL conical adapters can accommodate 5mL round bottom tubes with proper inserts — verify your rotor specifications before spinning. For phenol-chloroform extractions: polypropylene resists the organic phase during brief spin contact, but avoid prolonged storage of organic solvents in these tubes. Common lab reagents — ethanol, isopropanol, DMSO at typical working concentrations, and mild acids/bases — are compatible for standard protocol durations. Autoclave with the cap open to allow pressure equalization; close caps after cooling.