Gilson 215 manual Minimizing Cross-Contamination

Appendix

Pipetting Techniques

D

Minimizing Cross-Contamination

Cross-contamination of samples is caused by sample carryover on the probe tip or on its inner walls. Several methods are available to minimize cross-contamination.

•Use of the liquid level sensing capability will reduce carryover by limiting immersion below the liquid surface.

•Cleansing the probe tip with a flowing rinse removes contaminants from the external surfaces of the probe.

•Dispensing liquid through the probe into the rinsing station will eliminate internal contamination.

An alternate internal/external cleansing using a non-flowing rinse is also possible. (Internal rinsing may not be required at all if large diluent volumes are dispensed immediately after dispensing of the sample - a common practice in dilution procedures.)

D-2