Raisins

For the desired sample amount, we recommend using our single use vessel for comminution. With 30 grams of sample, the 40 ml vessel could barely be closed; we would recommend using the 100 ml single-use-vessels instead. To embrittle the sample, we recommend wearing the proper protective equipment.

The sample was placed into the cap and a small amount of liquid nitrogen war poured into the cap to cover all raisins. We waited until the nitrogen evaporated completely, before the vessel was closed and fixed on the mills adapter.

The mill was set to comminute in intervals of 10 seconds at maximum speed. The grinding sound vanished after the third interval was started. So grinding was interrupted after a total grinding time of 30 seconds and the ground sample material was poured out onto a sheet of paper. The still frozen sample started to melting directly where contact to the paper sheet was present. A majority of the raisins was comminuted to a fine powder. Some fragments with a length of ~ 500 µm were spotted inside the heap.

Even after five minutes at room temperature, there was a core of frozen powder inside the sample heap. We would recommend to place the ground sample into an exsiccator to prevent moisture condensing on the surface of sample.

Because of the high sugar content and moisture, the sample stuck together and was not free flowing again.