Top 10 Tips to Avoid Contamination in Pipetting
When it comes to quality control, pipetting is an imperative step in your beverage, cell culture and Chemical & Consumer Care processes. The risk of contamination can be kept to a minimum by always employing the best maintenance practices.
Get to know the top 10 short and easy tips to avoid contamination in pipetting, including:
- Avoiding splashes
- Using stands for storage
- Regular cleaning of equipment
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Clean Your Pipettes Regularly
For everyday cleaning use 70% ethanol to wipe pipette. If you use other decontamination agents, remove the residual detergents with distilled water. Choose pipettes with easy-to-clean design to ensure easy disassembling without tools. Use fully autoclavable pipettes in contamination-prone workflows and follow the manufacturer’s auto claving instructions.
Use Safe-Cone Filters or Filter Tips
Safe-Cone filters protect the pipette from contamination and volatile liquids. It is recommended to change the filters daily (after 50 to 250 pipetting) and always in case of overaspiration. Filter tips gives the best protection for both the samples and the pipette. Choose filter tips that have sufficient space between filter and sample.
Choose Air-Tight Tip Wrapping
Air- and water-tight tip rack wrapping protects the tips from contaminants during storage. To leave the contaminants out, remove the wrapping just before placing the tip rack into the laminar flow hood.
Use Stands for Storage
Use stands to protect pipettes from contamination and spills on working surface. Stands also help protect your pipettes from falling, thus helping to keep them in pristine condition.
Check Tip Purity Certification and Testing Limits
Check the purity certification of your tips for testing limits to ensure they are strict enough for your experiment. Automated tip manufacturing, batch testing and strict testing limits are good indicators for assured tip purity.
Restrict the Chances of Contamination to Spread
Moving of pipettes from one laboratory to another is a common source of contamination. Pipettes should be clearly marked especially in contamination-prone workflows and not to be shared with other workflows and laboratories.
Be Smart in Multidispensing
During multidispensing, tips can carry over contamination if not changed between samples. Dispense reagents first and then add samples - with a tip change between each sample addition.
Ensure the Tip Sterility
When using pre-sterilized pipette tips, make sure the manufacturer’s tip sterilization process is certified and regularly validated and monitored. Remember not to autoclave filter tips because the polyethylene filters do not tolerate the auto claving temperature. When autoclaving pipette tips, make sure that the autoclave is functioning properly.
Avoid Splashes
Pipette with constant pipetting rhythm to avoid contamination by splashing. You should pipette viscous liquids slowly or use an electronic pipette in slow speed setting.
Use Tips Long Enough to Avoid Contamination of the Pipette
Contamination on the pipette can spread to the next samples. Choose pipette tips that are long enough to reach the bottom of your sample vessel without the pipette itself touching the opening of the vessel.
Frequently Asked Questions
Contamination of the pipette itself can be avoided by using manufacturer recommended pipette tips of proper length and employing slow dispensing methods to avoid splashes. When not in use, contamination can be avoided with regular cleaning and proper storage stands.
- Uneven operation of the piston
- Failure to pre-wet pipette tip
- Unnecessary wiping of pipette tips
- Not factoring sample temperature
- Improper pipette cleaning and maintenance
- Not accounting for liquid viscosity
Proper pipette decontamination depends on a variety of factors. When choosing cleaning and decontamination solutions for your equipment, consider the liquid or reagent that has been pipetted. You should also ensure the solutions will be compatible with the pipette materials..
- Pipette-to-sample: Pipettes or pipette tips transfer contaminants to a sample
- Sample-to-pipette: Contaminated samples enter the pipette body
- Sample-to-sample: Residual materials from a pipetted sample are carried over to a different sample
