As lab technicians, we can’t deny that mistakes happen—human error, broken machinery, environmental conditions, fatigue and the list goes on. At TTE, we make it a priority to help scientists avoid pipetting errors and reduce their risk of pipette mistakes as a preventative measure. Our belief is to address all contributors and minimize pipetting errors from a broad approach, of standardized pipette calibration or pipette repair services, pipette training of best practices and incorporating the use of high quality, comfortable pipette equipment. The following is our top 10 list of routine steps technicians can take to prevent pipetting errors from taking over. Give some consideration to these steps the next time you’re pipetting:
1. Clean and check your pipette daily: A contamination-free pipette ensures accuracy, so it’s important to clean the pipette before and after every use. Make sure to give your pipette a visual check to ensure it appears to be in working order and there is no damage prior to beginning work.
2. Service your pipette every six months: Depending on how accurate your results need to be, it’s important to have your pipette serviced, on average, every six months. This means completely disassembling the pipette for re-calibration and replacement of broken parts. If your lab doesn’t service its own pipettes, then it’s important to send equipment to a trusted “pipette doctor” like TTE to ensure reliable service.
3. Know proper pipetting techniques: If you’re new to pipetting or are a veteran who needs a refresher, make sure you are following these techniques when using a pipette:
- Practice a smooth and slow motion
- Pre-wet the pipette tip
- Hold the pipette vertically when drawing in liquid and at a 45 degree angle when dispensing
- Immerse the tip slightly into the liquid during aspiration
- Touch off the pipette on the sidewall of the container
4. Use the appropriate pipette: It’s important to use a pipette with a volume selection closest to the volume you plan to aspirate and dispense. The accuracy of your test will improve if there is a small difference between the volume minimum on the pipette and the volume being tested.
- Example: If you need to dispense 15 microliters, a 1mL pipette would be the wrong choice, whereas a 20 microliter pipette would be ideal.
5. Account for environmental conditions: Consider the consistency of temperature, pressure, humidity, etc. An inconsistent environment will affect the accuracy of your results as liquids are susceptible to all types of environmental changes. It is specifically important to take into account the sample temperature and dispense all liquids once before recording results.
6. Let your pipette adjust to the environment: It is recommended that you allow your pipette and all testing equipment to adjust if they are exposed to new conditions and temperatures. This way there will be fewer environmental variables affecting your results.
7. Keep your pipette safe: Your pipette is the key to precise results; don’t put it in harm’s way! Never hold your pipette when you’re not using it. Never put it down on the lab bench. Always keep it on a stand. Always store it in an upright position. By following these pipetting practices, you ensure your pipette is contamination-free and in tip top shape.
8. Take a break: If you find yourself in the midst of what seems to be an endless test, take a break (if possible). When your mind, muscles, and eyes are fresh, your results will show it; fatigue can promote sloppiness and mistakes. If you are performing a time-sensitive test and can’t take a break, remember to maintain good posture and keep your elbows in, and your arms out front.
9. Use a new tip every time: There’s a reason your lab seems to have an infinite number of pipette tips; it’s so you can use a new tip for every new liquid you test. A tip that is continually used for different tests and substances is susceptible to cross contamination. It’s like when a doctor changes his or her gloves before coming in contact with a new patient; a pipette servicer must change the pipette tip prior to testing any new substance.
10. Practice, practice, practice: Like anything, the more experience someone has the better the outcome is likely to be. A pipette technician with years of calibration experience will ensure the accuracy, reliability, and expertise necessary to provide proper performance assessment and maintenance.
Despite our best efforts, no lab technician is perfect and no pipette is error-proof. However, by following the above practices you can decrease the margin of error and lend confidence to both technician and customer, providing results that are as accurate and precise as they can be.