Ultracentrifuges and ultra-rotors of the department of General Instrumentation

The Department of General Instrumentation still offers the basic ultracentrifugation service to the scientists of FNWI. External users can contact the assistant if they want to use this equipment. Currently available are two units: one Beckman centrifuge in a standard laboratory and one Sorvall centrifuge in a MLII lab.

Standard laboratory - Room HG01.334

This unit consists of:

• One Beckman-Coulter Optima-XE-90 ultracentrifuge (CXE14C01)r (short (pdf, 361 kB) manual and full manual (pdf, 2,1 MB) ultracentrifuge, complete catalog (pdf, 14 MB))
• one Ti90 fixed angle rotor (rotor description (pdf, 108 kB) SN 13E 2800)
• For this 90Ti rotor Polycarbonate bottles are advised (assemblies with tap and screw cap; volume 10.4ml, catalog number 355603, max g-force 362000, k-factor 48, max speed 65000rpm)

Safety First!

Considering the huge G-forces (OFTEN >100 000 EARTH GRAVITY!!!) applied to rotors, buckets and tubes during a run, it is important to:

1. Get instructions from the GI person in charge
2. Always book ultracentrifuge and rotor in the GI Booking system
3. Take great care that the difference in weight between filled tubes remains CLEARLY below 50mg .
4. use only matching tubes (see manual catalogue # for each rotor), caps/screws, and to dry them at the outside
5. to follow all prescriptions on how to close and hang the buckets of swing out rotors
6. grease o-rings with a littlebit of white fat and screws with the brown fat
7. close the cover of rotors and use all bucket in swing out rotors and fill fixed angle rotor positions according to the manual
8. gently place the rotor on the axis of the centrifuge
9. NEVER exceed the maximum deration velocity (high density gradients like cesiumchloride gradients require special care; see specific tables for max speed then).
10. CLEAN BUCKETS, TUBE CAVITIES AND ROTORS after each run with a soft soap, rinse well and give a final rinse with demineralized water
11. fill in the logbooks.

ALWAYS ASK INTRUCTIONS FROM THE ASSISTANT BEFORE USING CENTRIFUGES FOR THE FIRST TIME AND FORWARD ANY PROBLEM TO THE ASSISTANT. In order to prevent accidents (see photograph of a crash here!) above rules of good practice should be strictly followed.

BECKMAN MATERIAL IN BECKMAN ULTRACENTRIFUGES AND SORVALL MATERIAL IN SORVALL ULTRACENTRIFUGES.

The exact mode on how to fill specific tubes and the arrangement of tubes within the rotor are rotor-specific. Therefore, consult the specific rotorbook available in the centrifugation room (in general pair-like/symmetrical loading). For the Ti 90 fixed angle rotor we recommend there-usable thick-walled polycarbonate bottles with screw caps.Open thin-walled polyallomere tubes should be filled up to 5-6 mm below the edge to prevent collapse. They often require special caps. Polyallomere quick-seal tubes require an own procedure (ask assistance). Thick-walled tubes have the advantage that they can be used with a smaller volume, however at least half of the maximum volume which is a few millimeter below the edge.

DIRT CAUSES CORROSION AND DANGEROUS CRACKS. Follow specific decontamination procedures in case of hazardous contents (see rotor manuals).

Calculation from rotor speed to G-force

The following relationship exists between the rotation speed of a rotor (rpm), the distance (r) between tube and center of the rotation axis and the Relative Centrifugation Value (rcf- G-force).

For the Beckman-Coulter 90Ti rotor, r(min) = 34.2 mm, r(average) = 55.4 mm, r(max) = 76.5 mm.

Discontinued equipment

The Sorvall Discovery 100 (SN 9800159) and the Sorvall Micro type RC-M150GX (SN 9802893) are discontinued; they have been removed from Room 3.069 RIMLS. The Beckman L-70 (SN LOJ732) has been given to the department of Molecular Biology (RIMLS). This group uses the 70.1TI fixed angle rotor (SN 93E1695; derated to 56 krpm) approved by Beckman-Coulter.