Setting a pipette calibration routine: when should I get my pipettes serviced?

pipette calibration

Q:  My manager keeps suggesting that I get my set of pipettes serviced and calibrated. I have been working with the set of pipettes for three years and they seem to work just fine. My fear is that when I send them in, they won’t perform the same. After all, “if it isn’t broken, don’t fix it.” When should I get them serviced?

People have many reasons for why not to have their pipettes serviced. Whether they just don’t have the time, can’t part with their pipettes because there is so much work to do, or the pipette just won’t be the same (performance, feel), etc.

If you or your colleagues have bad experiences with your pipettes after being serviced, talk to your service provider. If they won’t work with you, maybe it’s time to find a different service provider or bring the activity in-house. If you have heard from other people that pipettes come back different, ask them exactly what they mean. Often, people unknowingly do something that alters the pipette performance after it returns, or it has been several months since the service and the pipette’s performance has degraded. A few probing questions and a little investigative work can often reveal the real issue.

Why it makes sense

Keep in mind regulated labs are frequently required to verify pipette performance upon return from service [e.g., ISO 17025 or FDA cGMP labs]. Whether or not your lab is regulated, it is still prudent to check the performance and functionality of your pipette on a periodic basis.

It is imperative for pipettes to be serviced regularly. They are mechanical devices that are the workhorse of most scientific laboratories. They contain many moving components that need to be inspected: tip shaft, piston, seals, dial and springs. Even if all of these components are working properly, the pipette should be checked for performance to ensure accurate and precise dispensing. Just like a car needs to have its oil changed regularly, pipettes need regular service to keep things operating properly for the long term. The frequency of service can be decided by tracking the performance of your pipette and understanding the samples and pipetting workload. In other words, if your normal service interval is yearly, but after four months you notice the plunger begins to stick, then it is appropriate to increase the frequency according to your needs.

A few things you can look for

Even if you get your pipettes serviced regularly, there are several signs that indicate when a pipette needs to be serviced.

  • Have you ever dialed in the volume and the plunger doesn’t move, then you press the plunger to “unstick” it? Well, it’s time to have it serviced. It may seem to work fine for now, but the piston seals will eventually fail.
  • If the orifice has salt deposits on the inside, it’s time to have it serviced. Salt deposits indicate that liquid has dried inside the pipette shaft and likely has worked its way into the seals.
  • Similarly, if you have aspirated liquid past the tip and into the pipette, and then have simply blotted the liquid out onto a paper towel, then it’s likely time to service the pipette. Tapping gently on a towel removes the majority of the liquid, but if there was enough force to aspirate fluid in the pipette, then it likely made it into other working parts.
  • If you have to use force to get the tips to make a good seal, then it might be time to service the pipette. In this case, the pipette shaft could be damaged or deformed and may need to be replaced.

Finally, if performance is unreliable, or it seems that there is only one person who can get a particular pipette to work, then it’s time to get it serviced. These instruments are too vital to the efficiency and data integrity of your lab to overlook their care and well-being.

Additional Resources

About the Author

Nat-HentzDr. Nathaniel Hentz, Vice President, Artel.  Prior to joining Artel, Dr. Hentz was the Associate Director of the BTEC Analytical Lab at North Carolina State University, as well as two years as Sr. Research Investigator at Bristol-Myers Squibb and seven years at Eli Lilly RTP Laboratories in North Carolina. Dr. Hentz received his Ph.D. in analytical chemistry from the University of Kentucky in 1996 and joined Lilly as a postdoctoral scientist the same year.