MIXER MILLS SAMPLE PREPARATION OF PLANT MATERIAL
Plants are used in many ways, for exam- ple, as food, in the paper manufacture or for the production of secondary fuels. Due to their ligneous components (such as lignin), plants are often fi brous. Lig- nin is a very stable substance which can cause problems, for example, in animal feed or in the production of bioethanol. In order to make specifi c improvements in these areas, research- ers need to understand exactly how lignin is produced in plants. With a growing understanding of the produc-
tion process of herbal substances, the content or the structure of lignin can be changed via targeted biotechnolog- ical manipulation. Plants with modifi ed lignin may lead to better digestibility in cattle feeding; or the bleaching of these plants in the paper manufacture is easier, and thus more environmen- tally friendly. In research often only small amounts of plant material are available for analysis. The MM 400 is the ideal mill to prepare small sample volumes. Six pieces of the thale cress
plant (Arabidopsis thaliana) were ground in the MM 400 to a fi nal fi neness of 100 microns for subsequent analysis. Even after a short grinding time, the sample was homogeneous, i. e. no coarse components or fi bers could be found that might have interfered with the subsequent analysis.
arabidopsis thaliana 6 plants (approx. 2 g)
after manual preliminary size reduction
after fine grinding in the MM 400
50 ml grinding jar of stainless steel, 1x25 mm grinding ball of stainless steel, 30 Hz, 2 min
MIXER MILL TECHNOLOGY
The grinding jars oscillate in a horizontal bow movement. The inertia of the grind- ing balls in the oscillating jars leads to a powerful impact of the balls on the round- ed ends of the jars. The sample is pul- verized in seconds to minutes and thoroughly mixed. If many small balls are used, the effect of friction is ampli- fi ed, so that it is even possible to disrupt biological cells.
FLEXIBILITY THANKS TO EXTENSIVE ACCESSORIES
Various grinding jar sizes and mate- rials make the mixer mills highly ver- satile instruments. Jars made of stain- less steel are available from 1.5 to 25 ml (MM 200) or 50 ml (MM 400). For applications in which neutral-to-anal- ysis work is important, materials such as tungsten carbide, zirconium oxide, agate, or PTFE are used. The grinding
Conclusion
The RETSCH mixer mills MM 200 and MM 400 are versatile, compact benchtop models that are specifi cally designed for grinding small amounts of sample. They mix and homogenize powders and suspensions in seconds and are also ideally suited for cell disruption.
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jars for the MM 400 permit the use under cryogenic conditions, thanks to their gaskets and screw-top lids. For such applications, RETSCH offers the KryoKit, in which jars can be cooled at -196 °C in liquid nitrogen and the sam- ple can be embrittled inside the jar. The mixer mills are frequently used for cell and tissue disruption in DNA/
RNA extraction. For this application, adapter racks are available that can be fi tted with up to 20 reaction vials. Grinding parameters such as frequen- cy and grinding time can be set conve- niently via the display. Up to 9 SOPs can be stored, in order to facilitate routine grinding processes.
Direct contact: 866-473-8724
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