|100 % < 1 mm|
|After a manual precutting to ~ 7 cm and smaller, our Knife Mill PULVERISETTE 11 can be used to comminute desired sample amount.|
speed: (interval) 6000 revolutions per minute
vessel: 1,4 L scratch-resistant plastic PC vessel
knife: Standard knife made of stainless steel
lid: Standard lid made of silicone
||(seeds ~ ) 1 mm|
The pineapple was precut into fragments < 70 mm for feeding. Desired sample amount of 450 grams fitted into the 1,4 liter standard vessel without problems. The grinding vessel was equipped with our standard knife and silicone lid.
We programmed an SOP to start comminution in intervals with 2.000 rpm for two seconds (two cycles). Afterwards, 10.000 rpm were set for two seconds of grinding. After each cycles, a pausing time of two seconds was programmed to guaranty that adhesive piece would slide back to the bottom of the vessel.
After 5 cycles (10 seconds of total grinding time), still a lot of fragments about 2-3 mm length were found. The volume of the sample collapsed to ~ 20 %.
Afterwards, we programmed 30 second intervals with 6000 rpm speed setting. Between 70 seconds of total grinding time and 100 seconds of total grinding time, we have not recognized a significant improvement. Still particles of ~ 1 mm length / width could be spotted.
A further improvement might be possible when the sample would be embrittled with liquid nitrogen.
We scraped out the sample and cleaned the equipment with a typical amount of water and dish washing agent. After 10 seconds at maximum speed, the vessel was flushed with fresh water and the knife was taken out for faster drying.
|Pictures:||The pineapple was precut into slices < 70 mm.|
|After the first 10 seconds, still fragments of the peal and seeds were visible.|
|After 100 seconds, seeds and tiny peal fragments persisted. The fineness did not improve any further with our standard knife.|