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Inspection
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Rotor Balancing
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Cleaning
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Sterilization
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Effects of Chemicals
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Inspection Guidelines
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Inspect centrifuge tubes and bottles carefully before each use.
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Centrifuge ware is subjected to high g-forces while spinning, which can lead to
failure. Safe laboratory practice requires that all centrifuge ware be
inspected before each use. Plastic centrifuge ware is easy to inspect; it
requires no special equipment. Initially, the effect of excessive stress in
plastic can be seen as cloudiness and discoloration or as "crazing", i.e.
minute cracks visible when the tube is held at an angle in front of a bright
light. With continued use, a crazed tube will develop larger cracks or will
fail. Tubes should be discarded if cracks are readily visible to the unaided
eye.
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Rotor Balancing
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Consult your centrifuge operator's manual for instructions on rotor balancing
and handling. Proper rotor handling, cleaning, and balancing are extremely
important. Because plastics have different densities, tubes and bottles of
different styles or materials should not be arranged randomly in the rotor.
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All centrifuge ware must be at least 80% full for proper performance, unless
otherwise noted.
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Cleaning
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Disposable Tubes
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Disposable centrifuge ware should be discarded after one use. NOTE: When
handling hazardous materials, decontaminate tubes prior to disposal.
To clean reusable NALGENE centrifuge ware, we suggest the following procedure:
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To loosen any residuals, presoak the tubes or bottles in NALGENE L900 detergent
(see General Cleaning for specific recommendations).
Soak overnight to loosen stubborn residue.
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Remove residue with a non-abrasive brush, or with a rubber or fluoropolymer
policeman.
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Wash and rinse product thoroughly, with distilled water as a final rinse.
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Air dry.
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Sterilization
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PP, PPCO, PMP, FEP and ETFE products can be autoclaved repeatedly under normal
conditions, 15 minute cycle at 121C/15 psig (1.02 bar). PC and PSF products can
be autoclaved under these same conditions, but autoclaving will cause
deterioration in mechanical strength and will shorten their usable life. If you
autoclave PC or PSF products, follow the Inspection
Guidelines above.
When autoclaving NALGENE centrifuge ware, follow these guidelines:
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Clean and rinse tubes or bottles thoroughly with distilled water before
autoclaving.
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For bottles or tubes with closures, remove closures (cap and plug) completely
before autoclaving to prevent collapse of container when cooling.
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Certain chemicals which have no appreciable effect on resins at room
temperatures may cause deterioration at autoclaving temperatures. See the
Centrifuge Ware Chemical Resistance Chart for specific chemicals and resins.
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All NALGENE centrifuge ware can also be sterilized with ethylene oxide gas or
compatible chemical disinfectants. More information is available on
Sterilizing NALGENE Labware.
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Effects of Chemicals
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Chemicals can affect the strength, flexibility, surface appearance, color,
dimensions, and weight of plastic parts. Chemical resistance is influenced by
temperature, duration, and frequency of exposure, chemical concentration, and
centrifugal force. Physical changes which may be caused by chemical exposure
include:
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Absorption of solvents, resulting in softening or swelling of the plastic
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Permeation of solvent through the plastic
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Dissolution of polymer in the solvent
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stress-cracking, which may occur as a result of chemical exposure combined with
external stress of centrifugal forces on tubes or bottles, which can be
worsened by improper fit in a rotor cavity
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Refer to the Centrifuge Ware Chemical Resistance
Chart for information on specific materials.
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A Note On the Unbreakability of NALGENE Centrifuge Ware:
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NALGENE centrifuge tubes and bottles should not break or crack if used in a
properly fitting rotor and run
according to our recommendations regarding chemical resistance,
temperature limits, relative centrifugal force ratings, use of closures,
washing, and autoclaving. If the limits are exceeded, the tube or bottle may
fail during centrifugation (i.e., may crack or break). However, unlike glass, a
NALGENE tube or bottle will not shatter, thus minimizing the risk to users and
equipment.
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