Gradient Formation And Fractionation; Labware Types; Polypropylene Tubes; Open-Top Polypropylene Tubes - Beckman Coulter Avanti J Series Instructions For Use Manual

Gradient Formation and Fractionation

Consideration should be given to gradient formation and fractionation when choosing a tube for a
density gradient run. If the bands or zones formed during centrifugation are indistinct, they may
not be visible through a translucent material such as polypropylene. If optimum band visualization
is important, Ultra-Clear, polycarbonate, or cellulose propionate tubes should be used. Whenever
collection of bands or zones must be done by slicing or puncturing the tube, a thin, flexible tube wall
is required. Ultra-Clear or polypropylene tubes should be used in these cases, depending on the
need for transparency.

Labware Types

NOTE
Tubes made of cellulose nitrate were formerly popular for various separations, particularly rate-zonal
separations. Beckman Coulter discontinued the use of cellulose nitrate for tube manufacture in 1980, due
to inconsistent physical properties inherent in the material. If you currently have cellulose nitrate tubes,
dispose of them. Consult your laboratory safety officer for proper disposal procedures.

Polypropylene Tubes

Polypropylene tubes are translucent or transparent in appearance, depending on wall thickness,
and are non-wettable (although some polypropylene tubes can be chemically treated to make them
wettable). Polypropylene tubes are reusable unless deformed during centrifugation or autoclaving.
Polypropylene tubes have good tolerance to gradient media, including alkalines. They are
satisfactory for many acids, bases, alcohols, DMSO, and some organic solvents. They can be used
with or without caps in fixed-angle rotors. Speed reduction is sometimes required with these tubes
if run with less than full volume (refer to your rotor manual). Several types of polypropylene tubes
are available.

Open-Top Polypropylene Tubes

Thinwall open-top tubes are used in swinging bucket and fixed-angle rotors. In swinging-bucket
rotors, thinwall tubes should be filled to within 2 or 3 mm of the tube top for proper tube support.
Caps are usually required in fixed-angle rotors. Thinwall tubes are designed for one-time use and
should be discarded after use.
Thickwall open-top tubes offer the convenience of centrifuging partially filled tubes without
tube caps in fixed-angle and swinging-bucket rotors. Because the solution reorients during
centrifugation, the maximum partial fill volume depends on the tube angle. For greater fill volumes,
use tubes with caps. Refer to the applicable rotor manual for fill volumes and speed reduction
requirements. Thickwall polypropylene tubes are typically reusable unless deformed during
centrifugation or autoclaving.
PN JR-IM-10AG
Tubes, Bottles, and Accessories
Labware Types
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