Calreset; Recommendations For Accurate Pipetting - Thermo Scientific Matrix MultiChannel Equalizer Pipette User Manual

With expandable, equal tip spacing

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D.2.5 CALRESET

CALRESET allows you to return to a default calibration step. To reset the

calibration, enter the CAL mode using the Special Function key. When the

calibration point is displayed, press the [Purge] key. The display flashes

"FACT," "CAL," then "SET" and the pipette resets to the default step. This

default setting is an average value for all pipettes of its class. This value may

differ from the factory-optimized calibration step documented on the

"Pipette Calibration Report" enclosed in this pipette's documentation.

D.3 Recommendations for Accurate Pipetting

Equalizer pipettes are factory calibrated to deliver accurate volumes with

distilled water at 20 °C. By using the calibration procedures described

above, you can pipette liquids of different specific gravity with a high degree

of accuracy and reproducibility. For optimal pipetting results, refer to the

following recommendations:

• Pipette at a constant temperature. Allow liquids and equipment

to equilibrate to ambient temperature. Volume aspiration with air

displacement pipettes varies with air pressure, relative humidity and the

liquids vapor pressure, all of which are temperature dependent.

• Attach tips with slow, even pressure. When applying tips, avoid

'banging' or applying excessive force to the tip(s), as this stretches the tip

seal and will affect volume. Use Matrix tips, which have been specifically

designed to match the tip fittings on Matrix pipettes.

• Calibrate the pipette for the liquid. If the liquid has a specific gravity

and vapor pressure equivalent to distilled water, calibrate using "EASY"

CAL mode. Otherwise, use "CALC" mode.

• Pre-wet the pipette tip. Aspirate and dispense a few times before

aspirating the liquid to increase humidity within the tip, reducing

sample evaporation that results in lower dispense volumes in initial few

pipettings. The need to pre-wet increases when working with liquids with

high vapor pressure and/or high surface tension.

• Immerse tips fully. Tips should be immersed approximately ¼ inch

(approx. 0.6 cm) below the liquid's meniscus and away from the

container surfaces to avoid aspiration of air and excess droplets clinging

to the outside of the tip.

• Discard a primer volume. When the motor changes from aspiration to

dispense, the percentage of error is greater in the first dispense than in

subsequent dispenses.

Calibration

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