Gloriosa Superba fruits (dry)

The 15 ml bowl use to be filled to the almost to the maximum with 2 g of sample. A grinding of higher amounts (8 g as requested) might only be possible by batch wise grinding.

After the first minute of grinding, the dry flesh of the fruits uses to smear to the balls and bowl. The seeds still remain intact. Even with longer grinding times, seeds use to stay intact. A grinding with Mini-Mill PULVERISETTE 23 is not recommended.

The sample has been discarded.

After a first dry grinding time of 3 minutes, all seeds stayed intact. To check if the result might be improved by grinding in suspension, about 7 ml of isopropyl alcohol have been added and the sample has been ground for a total of 10 minutes. Dry fresh got a mushy paste, but seeds use to remain intact.

The sample has been discarded.

Even with higher setting of amplitude, the seeds remain intact. A grinding is not possible as shown. The sample has been discarded.

Probably it might be possible to grind the sample after it has been embrittled (see result 4).

The desired amount of sample has been placed into the mortar and has been fixed to the Vibratory Micro Mill PULVERISETTE 0 inside of the Cryo-Box. Liquid nitrogen has been used to chill the sample and mortar before grinding. During operation, liquid nitrogen can be filled by the feeding funnel to compensate loss by evaporated nitrogen. Only one minute of grinding use to be fulfilling to achieve < 1 mm particles. Longer grinding times are still possible to maintain a finer result.

We are guessing that also the present Variable Speed Rotor Mill PULVERISETTE 14 will be capable to grind down embrittled sample by spoon wise feeding.