Labware Cleaning: Pre-soaking Pipettes

Q. Why is it important to pre-soak pipettes in 1% Alconox or Liquinox before cleaning in a pipette siphon washer with Alcotabs?

A. The most common problem in lab pipette cleaning is residues that dry on after use and prior to cleaning. This problem is attributed to the failure to pre-soak the pipettes immediately after use. At Alconox Inc., we recommend placing soiled pipettes in 1% Alconox® Powdered Precision Cleaner or Liquinox™ Critical Cleaning Liquid Detergent,  solution immediately.

For the purpose of detergency, it does not matter if pipettes are place tips up or tips down during pre-soak. The important thing is to make sure the pipette is completely immersed in solution with no part exposed to air where there would be a meniscus to potentially leave a ring or even an etch on the pipette. For fewer broken pipette tips, it is recommended to place pipettes tips upward, if possible.

However, for cleaning extremely viscous or difficult residues there is possibly a theoretical advantage to putting the pipettes in tips down to pre-soak because when they are lifted out of the pre-soak any loosely adhered residue or particulate will drain out the bottom and not have to pass thru the entire length of the pipette before it is removed.

For more information about any one of our Alconox Inc. Cleaners, consult the specific technical bulletin for each product HERE. Or click here to access each of our detergent’s Safety Data Sheets. You can also request a free sample of the above, or any Alconox Inc. detergent by completing the questionnaire at Get Sample.