Loss of a perfect pipetting aid

27 August 2025 Tags: M-Sarpette Peleus ball pipetting aid liquid handling

When I first started at university, the laboratory landscape was more analogue. The pipetting arsenal, at least that of students, consisted of a single device: the humble Peleus ball, a manual pipetting aid.

The Peleus ball: simple yet confounding

The Peleus ball was very simple. Three valves orchestrating a careful dance of vacuum and release. The top valve opened to evacuate the main ball. Press the bottom valve to draw liquid into the pipette, then use the third valve on the side-arm for gravity-flow release. For complete emptying, you would simply press the small rubber ball at the junction point of the side arm - without pressing any of the valves.

I loved everything about the Peleus ball. It was incredibly cheap, virtually indestructible, and delivered precise control in experienced hands. But therein lay the problem: the "experienced hands" part. Students found the logic confusing despite its inherent simplicity. More often than not, they'd press the wrong valves, inadvertently sucking copious amounts of liquid into the ball, contaminating media, and other laboratory sins. In addition, the Peleus ball is lacking a filter between the ball and pipette, creating contamination risks, both for the ball and the liquid that was pipetted.

Enter the M-Sarpette from Sarstedt

For students the M-Sarpette turned out to be a good option, as somehow they grasped the concept quicker, even though the general principle is exactly the same as that of a Peleus ball. In essence, the M-Sarpette is the Rolls Royce version of a Peleus ball. It features a simple rubber ball that could be squeezed without pressing anything, and an intuitive slider for liquid control. A small rubber button provided complete pipette emptying when needed.

And even though costs twice as much as a Peleus ball, it still was way cheaper than the electric pipetting aids. What's more, it included a sterile filter for contamination protection. Students still needed practice, but after brief training, they typically mastered it. The M-Sarpette struck the perfect balance between precision, user-friendliness and low costs.

For years, this was my go-to solution. We use M-Sarpettes constantly, and I regularly ordered spare filters to replace those inevitably wetted by overly enthusiastic students.

The Devastating Discovery

Just recently, I prepared another routine order for a M-Sarpette, replacement filters and other related items, sending my quote request to Sarstedt along with other needed items. The reply came promptly - but with a surprisingly short quote. The M-Sarpette, filters, and related products were absent.

With a sinking feeling, I wrote back asking if the M-Sarpette had been discontinued. The response was typically German, brief and to the point: "Yes."

This was bad news. Without replacement filters, existing M-Sarpettes become useless, and so far I've been unable to source alternatives anywhere. Personally I would love to simply return to Peleus balls, but students, especially when visiting the lab only briefly, for example for their Final Year Project, simply are unable to adapt to their complexity.

The Electric Alternative: Function Without Soul

Reluctantly, I purchased a modern electric pipetting aid from SLS.

On paper, it has all you could want: three modes including slow and fast sucking/dispensing, plus pump-assisted sucking with gravity-fed release for multiple volumes. It performs exactly as advertised.

And I absolutely hate it! I hate it as much as I have hated any electronic pipetting aid I tried before. I always found them clunky, imprecise and for that reason slow, this new one not being an exception. Surprisingly, my students - despite initially rejecting the M-Sarpette as being an archaic way of liquid handling - hate it too and avoid using it as long as some of the M-Sarpettes are working. They describe it in the same way: clunky, imprecise and slow. It has nothing to do with the specific model - as said, it works perfectly fine. It is simply not as good as the good old analogue alternative, at least in the way we are using it in our lab.

So here is my plea: Please, Sarstedt, please put the M-Sarpette back into your catalogue!