Pipettor Calibration and Care

Automatic Pipettors - Calibration Check

  1. Weigh a tube that is large enough to contain the volume to be pipetted.

  2. Accurately aspirate a volume of distilled water and dispense the water into the weighed tube.

  3. Reweigh the tube.

  4. Subtract the initial weight of the tube from the weight of the tube with the dispensed water, the second weight reading. The change in weight should equal the volume dispensed.

  5. If the weight is more than 10% off, consult with the lab instructor. To recalibrate the pipettor you must use the instructions specific for the instrument you are using, the instructions are available from the manufacturer, or send the pipette to the manufacturer for repair and calibration.

  6. When working with small volumes, under 10 ml, you should pre-wet the pipettor tip, see the [Pipette Care, Limitations, and Safety section for instructions].

Pipettor Care, Limitations, and Safety
1. Do not operate the pipettor without a tip and do not allow any liquid in the pipettor. To prevent liquid from entering tip make sure the volume to be pipetted is appropriate for the tip and the pipettor and do not lay down or invert the pipettor when a filled tip is attached.

2. Pippettors should be cleaned in a soap solution and sterilized with 60% alcohol. Then they should be rinsed with distilled water and dried. Pistons and o-rings should be lightly lubricated when cleaned or replaced with silicon grease provided by the pipettor manufacturer.

3. Tips must be disposed of properly. If the tip is contaminated with culture or body fluids dispose of tips in the biohazard waste container. If contaminated with hazardous chemicals dispose of in a suitable hazardous waste container.

4. Do not pipette organic solvents or clean the pipettors with organic solvents. Some organic solvents will damage the seals of the pipette.

5. To ensure accuracy of pipetting, check the volume that is dispensed if you are pipetting liquid or tips with a different temperature than the pipette, for example cold solutions, or pipetting liquids with very different physical properties from water, for example glycerol, or liquids with a high vapor pressure

6. When working with small volumes, under 10 ml, you should pre-wet the pipettor tip by aspirating and dispensing liquid two to three times. This compensates for the volume of liquid that coats the inside of the pipette tip. This small volume can be significant when pipetting very small volumes.

7. When pipetting high-viscosity solutions wait a few seconds after drawing liquid into the tip before withdrawing the tip from the stock solution and wait again a few seconds when dispensing the liquid.

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