MISSION 4: Olympic National Park

The final mission of the Extreme Pipetting Expedition was carried out at Olympic National Park, where the effect of humidity on pipetted volumes was studied. Humidity was chosen as the focus of Mission #4 because many regulatory standards recommend that pipette calibration take place in environments with 60 percent relative humidity. However, laboratories commonly operate at about 15-30 percent relative humidity. ARTEL compared pipette performance in the humid environment of Olympic National Park to performance in a typical laboratory to determine the effect of humidity on pipetting accuracy.

Olympic National Park was chosen as the location for Mission 4 because it is known for its plush, rainforest-like environment. The Park is home to 266 glaciers, over 60 miles of Pacific coastline, and temperate conditions, with 140 to167 inches of rainfall each year.

THE EXPERIMENT

For this mission, a set of pipettes were tested in five different locations ranging from high to moderate relative humidity (RH).  The two highest humidity conditions were at Rialto Beach (14°C & 74% RH) and Olympic Inn (20°C & 60% RH).  Two other locations were chosen that represent the range of more typical laboratory conditions (22°C & 40% RH and 21°C & 22% RH).  The accuracy of each pipette at these four locations was compared to accuracy measured in ARTEL’s accredited (ISO 17025) calibration laboratory.  The effect that humidity has on precision was assessed by comparing CV at each location against the manufacturer’s specification.

As in previous missions, pipette performance was tested in the field using the ARTEL PCS® Pipette Calibration System.  Based on ratiometric photometry, the system is portable and unaffected by most environmental conditions.  To ensure consistency in pipetting technique, the scientists performing this work were trained and certified using the Artel Method™.