Stir bar retriever
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A stir bar retriever or simply stir retriever is a rod-shaped lab item used to recover stir bars from flasks or reaction solution, without contaminating the latter.
A stir bar retriever consists of a PTFE long rod about 20-30 cm or longer, which has a thicker end, where a magnet exists, also covered in PTFE. Some models may have a small ring at the other end, which allows the retriever to be hung on a nail or a wire.
Stir bar retrievers can be purchased from lab suppliers. They can also be found online.
DIY stir bar retriever
A very simple stir bar retriever can be made by taking a plastic (PP) tube, seal at one end, add a small magnet in the tube, then seal it at the other end.
Another alternative is to take a broken volumetric pipette, cut it near the bubble level, seal it at the cut, then fill the bubble with small magnets or pieces of small magnets, then seal the glass tube at the other end to make sure no air or reagents enter the tube.
If you're lazy, you can simply place a strong magnet to the bottom of the flask to attract the stir bar, then slowly move the magnet with the stir bar until you get it out of the flask.