QIA symphony

[bcollet]

Dear all,
I have some colleagues who experience some problem with a QIAsymphony automatic RNA/DNA purification system - some cross-contamination between samples occur.
Is there any other users of this system that experience the same problem - or is it an isolated case?
thanks for any feedback,
Bertrand

[rluqman]

Dear Bertrand,

Have you tried to observe the extraction procedure from start to end. By doing that you would be able to notice where the possible cross-contamination could have taken place. While working with the Qiasymphony I did notice that the tip holder loose the calibration and they end up touching the side of the elution tubes when the protocol is at its final stage of eluting the DNA/RNA, when this occured the tubes (if they are not sitting tightly in the elution rack adaptor) tend to get pulled up by the tip(s) during the upward movement after elution has taken place followed by dropping back into their position, this can lead to micro splashes of the DNA/RNA between different tubes. When this happened we had the engineer move the elution adaptor rack slightly to the left (in our case) rather than calibrate the tips (why? because if you calibrate the tips to centralise it to the slution tubes then it may affect its positioning for the regents, unit boxes and tips.). I would also reccommend that you check the seating of the elution tubes on the elution rack, the should sit properly and firmly, i would suggest puching the elution tubes using sterile gloves before closing the E-drawer.

Hope the above helps.

RL