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| Mixer Mills |
| model MM 200 and MM 400 from Retsch |
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| Grinding, mixing, disrupting small amounts of sample |
RETSCH Mixer Mills MM 200 and MM 400 are laboratory “all-rounders”. They have been developed specially for grinding, homogenizing and mixing of small sample
amounts in only a few seconds. They are also perfectly
suitable for the disruption of biological cells as well as
for DNA/RNA extraction. The MM 400 can also be used for wet and cryogenic grinding. |
| Benefits at a glance |
| • Quick, efficient pulverization
and homogenization • High sample throughput due to short grinding times and two grinding stations • Reproducible results by digital preselection of grinding time and vibrational frequency • Large range of grinding jars • Up to 9 parameter combinations can be stored • 2-year warranty, CE-conforming |
| MM 200 and MM 400 – high-performance mixer mills for many types of material |
| The RETSCH Mixer Mills MM 200 and
MM 400 are used for size reduction
and pulverization of hard, mediumhard
and brittle samples as well as
for soft, elastic or fibrous ones such as tissue, bones, hair, chemicals,
drugs, coated and uncoated
tablets, minerals, ores, alloys,
glass, ceramics, soils, sludge,
plant parts, cereal grains, oil
seeds, plastics, waste samples,
wool and textiles, to name but a
few. With their ability to process small sample amounts to analytical fineness quickly and reproducibly, RETSCH mixer mills are the ideal devices to prepare pressed tablets for subsequent XRF analysis. |
Mixer mills are primarily used
in the following sectors: • Agriculture • Biology and Biotechnology • Ceramics and Glass • Chemicals and Plastics • Environmental Research • Foodstuffs • Forensic Science • Medicine and Pharmaceuticals • Metallurgy and Metallurgical Engineering • Mineralogy • New Materials Research |
| MM 200 and MM 400 technology |
| The grinding jars perform oscillations in a horizontal position. The inertia of the grinding balls causes them to impact with high energy on the sample material at the rounded ends of the grinding jars and pulverize it. Also, the movement of the grinding jars combined with the movement of the balls result in the intensive mixing of the sample. The degree of mixing can be increased even further by using several smaller balls. If many very small balls are used (e.g. glass beads) then, for example, biological cells can be disrupted. The large frictional impact effects between the beads ensure effective cell disruption. |  |
| Maximum reproducibility |
 MM 400 |
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| Both mills are particularly easy to
use. The vibrational intensity can be
set accurately from 3 to 25/30 hertz.
An electronic speed control keeps
this value constant during the entire
grinding process. The grinding time
can be preset digitally in the range
from 10 seconds to 99 minutes.
All instrument parameters are retained
during standby operation for
subsequent processes. Up to 9 parameter
combinations can be stored.
At the same time this ensures the
highest degree of reproducibility for
the following sample preparation processes. Wet grinding The screw-top grinding jars provide the ideal preconditions for wet grinding with mixer mills. A Teflon seal prevents the escape of liquids and particles even at maximum vibrational frequency. |
MM 400 – the mixer mill
with unsurpassed
performance, safety
and comfort Due to the increased oscillation radius of the MM 400, the energy input is approx. 30% greater than that of the MM 200. This results in more fineness in less time. In addition, large grinding jars with a capacity of 35 ml and 50 ml are available for the MM 400. In these jars, up to 20 ml of sample material with a feed size of up to 8 mm can be ground. Clamping and removing the grinding jars is easy and safe. The special self-centering of the grinding jars ensures that they are always located in exactly the same position, which optimizes the reproducibility of the grinding process. The self-locking clamping device fixes the grinding jars with maximum security. |
| Advantages MM 400 |
| The Mixer Mill MM 400
is a real multi-talent with
nearly unlimited applications: • Reproducible dry grinding, e.g. for sample preparation for XRF analyses • Loss-free wet grinding due to screw-top, leak-proof grinding jars • Convenient cryogenic grinding of thermally sensitive products without long precooling times and with a minimum consumption of liquid nitrogen • Efficient disruption of plant or animal tissues or cell suspensions in adapter racks for 5 or 10 reaction vials |
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| Cryogenic grinding with the Mixer Mill MM 400 |
| Thermally-sensitive and elastic substances
can be successfully processed
by external cooling of the
grinding jars. However, jars made
from agate or ceramics should not
be cooled with liquid nitrogen in
order damage during the grinding
process. The screw-top grinding jars are particularly suitable for cryogenic grinding, as they remain hermetically sealed until they have regained room temperature. This prevents atmospheric humidity from condensing on the cold sample as water vapor which could penetrate the sample and falsify the analytical results. A special cryo kit is available for precooling the grinding jars in liquid nitrogen; it consists of: • 2 insulated containers • (1 and 4 liter), • 2 pairs of grinding jar tongs • 1 pair of safety glasses. |
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| Selection guide for mixer mills |
| The MM 200 is mainly used for the size reduction of small amounts of sample. |
The MM 400, with 30% higher energy, can pulverize samples finer and faster, with optimum reproducibility. Its |
convenient self-locking clamp allows the use of large jars up to 50 ml and pre-chilled jars of stainless steel. |
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| Cell disruption with RETSCH mixer mills |
| Smallest amounts of sample,
such as are normally used for the
isolation of DNA and RNA, can be
prepared in disposable reaction
vials (e.g. Eppendorf). Adapter
racks of PTFE which accommodate
either 5 or 10 disposable reaction
vials can be used for this. In the mixer mills, efficient
disruption is achieved so quickly
that no additional cooling is
necessary. Adapter rack for: 5 reaction vials 1.5 and 2.0 ml (1) 10 reaction vials 1.5 and 2.0 ml (2) 10 reaction vials 0.2 ml (3) |
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| Grinding jars and grinding balls for versatile use |
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| Screw-top grinding jars for MM 400 | Grinding jars with push-fit lids for MM 200 | |||
| The grinding result is greatly influenced
by the grinding tools. The
choice of jar volume, ball charge and
material depend on the type and
amount of sample. In order not to
falsify the subsequent analytical
determination, a neutral-to-analysis
material should be selected. The pulverization energy is determined by the density and weight of the ball material. The higher the ball weight and density, the higher the pulverization energy. The jar and balls should always be made of the same material. The table shown below is intended to help you to select suitable grinding tools. In addition to the standard grinding jars with push-fit lids for the MM 200, superior screw-top grinding jars for the MM 400 are available.
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| Mixer mills order data |
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