Pipette for PCR

Birgit Jostes 106007.414 at COMPUSERVE.COM
Fri Aug 30 06:41:16 EST 1996

Dear Yiu-Loon Chui,

our (i.e. Eppendorf in Hamburg) experiences are the following:
1. Filtertips are a reasonably priced tool to prevent contamination. 
BUT: Due to their physical principle they cannot be 100% safe because it
must be possible for air to pass through the pores. Therefore, it is
theoretically also possible that aerosols pass through. In addition, one
must be very careful not to have contact between the liquid and the filter
inside the tip. 
2. Positive displacement systems are working with an exchangeable piston
inside the tip. Therefore, after each pipetting step the tip and the piston
are discarded. The system guarantees 100% safety against
cross-contamination and aerosols. 
In addition, the accuracy is independant of viscosity, density or vapor
pressure of the liquid.
BUT: The tips are quite expensive :-(

Depending on your demands and budget, prevention of contamination can be
achieved with both systems. To be absolutely sure, a positive displacement
system should be used.

Dietmar Kahle, Ph.D.
Eppendorf-Netheler-Hinz GmbH, Hamburg, Germany
Marketing - Application Support

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