How quickly should the tabs be lifted up?
To minimize evaporation losses, lift each tab immediately after dispensing dye into its well. Lift the tab at a comfortable rate.
How hard do I need to push on the tab? How far?
A light touch is all that is needed to lift the tab, until you feel it stop moving. Do not push hard, or the plastic parts will distort and the glass capillary will break. Leaving the tab up will reduce evaporation, thereby providing you more time to compare the meniscus to the adjacent markings.
How do I avoid air bubbles?
When dispensing into the well, if you do a blowout, first lift the end of the pipette tip out of the pool of dye in the well.
How accurate is the Checkit?
It is about 1% accurate, aside from external influences such as evaporation.
What is the cross-hatched rectangle?
ISO 8655 standard covers the accuracy requirements of hand held, single channel, adjustable pipettes. The rectangle illustrates the acceptable range. Note that the width of the ISO rectangles does not factor in the 1% accuracy of the pipette Checkit.
What are the horizontal lines under some of the tick markings?
The horizontal lines represent the approximate accuracy of the Checkits. Thus, if the readings indicate that the dispensed volume was 3% low, and the horizontal lines indicate 1% accuracy, the actual dispensed volume might be only 2% low, or it might be up to 4% low.
Can the Checkits be used to test someone’s pipetting technique?
Yes, one good application of the Checkits is testing the accuracy of a person’s pipetting technique.
Can the Checkits be re-used?
No, the Checkits are designed to be disposable.
Can I replace the glass capillaries?
No. To ensure accurate readings, the capillaries are precisely positioned to within .001 to .002 inches (25 to 50 micrometers). It would be near impossible to refill the Checkit with such accuracy.
In what order should I test my pipette at the high, middle, and low end of its range?
We suggest that you test the high end of the range first, then the middle, and finally the low end. For example, with a C20 Checkit, first test it for 20 uL, then for 10 uL, and finally for 2uL.
Can I use the checkit outdoors?
For accurate readings, the Checkit must be on a level surface, near room temperature. It will not be affected by altitude, humidity, or small changes in temperature.
Is the Checkit’s performance effected by changes in temperature?
Temperature should not have a significant effect on the Checkit between 4-40°C and its readings change less than 0.07% with a 10°C change. The evaporation effects are minimal once the droplet is in the glass capillaries in the Checkit. Thus making it more accurate than a scale. While the density of the water changes (and so the observed mass for a given volume) between 4-40°C, the glass capillaries are not subject to much thermal expansion over this range. Therefore, the volume should stay very close to accurate between these temperatures. Since the Checkit measures pipette volume with volume, there is no conversion of units like with a scale (from mg -> mL). Given the volume on the Checkit is read in the same experimental environment of your pipette, it is a more accurate reflection of how your pipette performs. This is an advantage of the Checkit over classical methods.
How do I dispose of the dye?
The dye is safe and non-toxic. It can be disposed down a sink drain.