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Mixing samples

7 August 2019 Tags: mixing samples vortex

Especially when lots of dilution series are a regular part of the lab work the use of a good vortex mixer makes life a lot easier.

The preparation of serial dilutions has been a regular procedure in my lab for years. It requires mixing a large number of reaction tubes and in my experience having the right vortex mixer for this particular task can speed the process up very considerably. In a nutshell the most important parameters are a fast response, a fast speed-up time and no body movement of the mixer. I have come across all sorts of shapes and sizes, but currently we are using three different models in the lab.

Vortex Genie 2

For me personally the Vortex Genie 2 by Scientific Industries is the most suitable mixer on the market. These days it classes as a large piece of equipment, but its high weight means that the body never moves. The pressure point to start the mixing is just right, it is fast and the speed-up time is extremely fast. It also handles larger tube sizes such as 15 and 50 ml without any issue at all. We are using some smaller models mostly because of size considerations, but for dilustion series it is the model of choice.

Vortex Genie 2 variable speed vortex mixer produced by Scientific Industries

Purchased via Scientific Laboratory Supplies

Stuart SA6 mini vortex mixer

For me the Stuart SA6 mini vortex is the first realistic alternative to the Vortex Genie 2. With somewhat limited lab space size of the unit was an issue. However, the smaller units we sampled so far had pressure points that were to high, the speed-up time was very slow and the response time was not particularly good. The Stuart SA6 mini vortex mixer solves most of these problems. It is small and light-weight, but, importantly, the suction cups prevent it moving while it is in use and this system works very well. The pressure point is slightly too high, making it less comfortable than the Vortex Genie 2, but the mixing speed is excellent and the speed-up time is fast. For slightly more crowded bench areas it is an excellent alternative.

Stuart SA6 Mini Variable Speed Vortex Mixer produced by Stuart

Purchased via Scientific Laboratory Supplies

IKA lab dancer

Given the success of the Stuart SA6 mini vortex mixer we tried the Lab dancer produced by IKA. There is no doubt that this unit is very solidly built. However, it comes with a number disadvantages. The fixed speed is not a real issue – we rarely change the settings on the SA6. However, the unit comes with rubber feet rather than suction cup, which turns this unit indeed into a lap dancer: after relieving the pressure the unit rumbles on the bench surface for a couple of seconds, which is noisy and unhelpful, as the unit has to be re-positioned after a few mixing steps. It might well be possible that the unit can be fixed with sticky feet, but that somewhat negates the portability of this mini unit. The suction cups of the Stuart SA6 are by far the better option for our use. As with the Stuart SA6 the pressure point is slightly too high, making the unit less comfortable than the Vortex Genie 2 to use, but importantly the speed-up is slower in comparison to the SA6 and the overall speed is a touch too slow as well for the very rapid mixing that would speed up the process of serial dilutions. For the occasional use is unit is fine, but for heavy use we will continue to rely on the other two models.

Lab dancer fixed speed vortex mixer produced by IKA

Purchased directly via IKA Laboratory Equipment