NEWS RELEASE
ARTEL Extreme Pipetting Expedition Links Dry Heat to 35 Percent Error in Liquid
Handling
Visits Death Valley for Mission #3
Los Angeles, CA (November 7, 2007) – At Death Valley for Mission #3 of the Extreme Pipetting Expedition, ARTEL found
that pipettes under-deliver by up to 35 percent in dry and hot environments.
While volume delivery errors were partially reduced by pre-wetting pipette
tips, under-delivery still persisted, and the pipettes were found to operate
out of specification in most instances.
Laboratory technicians commonly encounter dry heat in their own work
environments, which, although not as extreme as Death Valley, can nonetheless
compromise assay results by affecting pipette performance. For example, laboratories using analytical instruments, ovens, incubators,
freezers and other devices requiring high power or open flames are prone to
heat and low humidity. Heating and air-conditioning systems not equipped with humidifiers may also
contribute to dry heat. To ensure pipetting accuracy and precision and
strengthen data integrity, it is essential that laboratory scientists
understand and compensate for this source of error.
ARTEL is releasing the results from Mission #3 at the Association for Molecular
Pathology (AMP) 2007 Annual Meeting and Exhibits (booth #54), November 7-10,
2007, at the Hyatt Regency Century Plaza Hotel in Los Angeles, CA. [See complete report here.]
“Laboratories often experience changes in humidity and temperature throughout the
course of a year and data may be at risk,” says George Rodrigues, Ph.D., Senior Scientific Manager, ARTEL. “Humidity and temperature can also vary across laboratories in different regions,
between laboratories on different floors, and even in different sections of the
same laboratory.”
Like in previous missions, error caused by the environmental conditions at Death
Valley was greater when pipettes were set to their minimum volumes than when
they were set to their maximum volumes. A two-microliter pipette set to deliver
its minimum volume of 0.2 microliter without pre-wetting under-delivered by
34.7 percent. Pre-wetting reduced the error to 30.9 percent, but the pipette was still
operating outside its minimum-volume accuracy specification of 12 percent. When set to its maximum volume of two microliters without pre-wetting, the
pipette under-delivered by 7.0 percent without pre-wetting and by 4.8 percent
with pre-wetting, both outside of the manufacturer’s accuracy specification.
When working with larger liquid volumes, errors were also induced by the hot and
dry conditions, but on a smaller magnitude. Without pre-wetting, a 20-microliter pipette at its minimum volume
under-delivered by 16.8 percent, which is a significantly lower inaccuracy than
exhibited by a non-pre-wet two-microliter pipette at its minimum volume (34.7
percent error). Pre-wetting the 20-microliter pipette prior to dispensing its minimum volume of
two microliters reduced error to 7.4 percent.
“Based on data taken at Death Valley, we highly recommend pre-wetting pipette
tips to reduce volume loss when pipetting in dry and hot environments,” says Doreen Rumery, Laboratory Technical Manager and Quality Control Manager,
ARTEL.
Liquid handling error experienced in dry heat is largely due to evaporation. The
evaporation of a miniscule amount of liquid inside the pipette tip has a large
effect on pipetted volumes, especially when target volumes are in the
microliter range. When one microliter of liquid evaporates, it converts into
more than 1,000 microliters of gas, expanding by a factor of 1,250 to 1,450
depending on temperature. This expansion prevents the pipette from aspirating the desired target volume.
A 3.3 million acre desert, Death Valley was selected as the site for Mission #3
because of its iconic hot and dry climate. Surrounded by mountains, the valley
captures and retains extreme amounts of heat to create one of the hottest
environments on earth, commonly exceeding 49°C (120°F). Death Valley is also the driest locale in the United States, receiving fewer
than two inches of rain annually.
The Extreme Pipetting Expedition is a multi-phase, year-long scientific study to
illustrate the impact of laboratory environmental conditions on pipetting
performance and data integrity. Previous missions explored how barometric pressure and how pipetting warm and
cold liquids affect data integrity. More information can be found at www.artel-usa.com/extreme.
# # #
ARTEL is the worldwide leader in liquid handling quality assurance. ARTEL manufactures the most accurate, precise and easy-to-use systems for
ensuring data integrity in liquid volume measurement. ARTEL systems, based on
proprietary Ratiometric Photometry, conform to ISO 8655-7 and provide
NIST-traceable results. In addition, ARTEL provides liquid handling quality
assurance support and consultation services including on-site pipetting
technique training and certification for pipette users and laboratory managers,
as well as Liquid Handler Performance Verification services for automated
laboratories. Since 1982, ARTEL technology has been proven in daily use in
thousands of laboratories including pharmaceutical, clinical, forensic, public
health and environmental. Leading institutions such as Amgen, ARUP,
Bristol-Myers Squibb, Celgene, Centers for Disease Control, DuPont, Eli Lilly,
FBI, Genentech, Genomic Health, Mayo Clinic, Memorial Sloan-Kettering Cancer
Center, Merck, Pfizer, Procter & Gamble and U.S. FDA depend on ARTEL technology to help them meet their
objectives for quality and productivity.