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The effect of filters on aseptic pipetting lifetime of mechanical and electronic pipettors and carryover during pipetting
Author(s) -
Kolari M.,
Mann S.,
Takala T.,
Saris P.,
Suovaniemi O.,
SalkinojaSalonen M. S.
Publication year - 1999
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1046/j.1365-2672.1999.00599.x
Subject(s) - pipette , barrel (horology) , filter (signal processing) , contamination , chromatography , filter paper , chemistry , materials science , composite material , biology , ecology , computer science , computer vision
The aseptic pipetting lifetime of air displacement pipettors during serial pipetting was investigated. When a Micrococcus luteus T culture was pipetted using no filter, less than 100 pipettings were required to contaminate the interiors of both mechanical and electronic pipettors with more than 10 3 cfu (n = 1890 pipettings). When a filter was placed in the pipettor tip cone, the sterility of the pipettor barrel was maintained for more than 500 pipettings (n = 2620) or 50–250 pipettings (n = 2520), depending on the filter type used. When a radioactive liquid or plasmid DNA was pipetted using no filter, contamination of the pipettor barrel occurred within less than 100 pipettings. A filter placed in the pipettor tip cone protected the interior of the pipettors against radioactive contamination for more than 250 pipettings and against DNA contamination for more than 500 pipettings. A pipettor barrel contaminated with M. luteus T caused carryover in 13% of the pipetting series. When a SCF filter was placed in the tip cone, no carryover was observed within 2620 pipettings. A tip cone filter replaced at intervals of 50–250 (polyethylene filter) or 500 (SCF filter) pipettings will protect the pipettor barrel from contamination and the samples from carryover.