Produced in Partnership with RETSCH GmbHReviewed by Emily MageeApr 4 2023
The Mixer Mill MM 400 is a high-performance ball mill produced by RETSCH, designed for grinding and homogenizing powders and suspensions within a few seconds. It achieves a fineness down to the low micron range, meaning it is a truly versatile laboratory instrument.
The MM 400 can simultaneously prepare up to 20 samples with its two grinding stations. It is suitable for reproducible dry grinding, such as for the preparation of samples for XRF analysis. However, the mill may also be utilized for loss-free wet grinding.
Figure 1. Mixer Mill MM 400. Image Credit: RETSCH GmbH
The mill is able to pulverize temperature-sensitive products via cryogenic processing, wherein the grinding jar and the sample it contains are cooled externally, and the sample is sufficiently embrittled to be pulverized to analytical fineness.
The MM 400 offers a wide variety of accessories, including grinding jars in different sizes and materials and adapter racks that are capable of holding five to ten reaction vials. These are used for the disruption of plant and animal cells and tissues.
Due to its flexibility, the MM 400 is used in a variety of industries, from plastics and environment to mineralogy, biology, and pharmaceutics.
Performance Data of MM 400
The performance data of MM 400 is detailed in the table below:
| Feed material |
soft, medium-hard, hard, brittle, elastic, fibrous |
| Feed size* |
<8 mm |
| Final fineness* |
<5 µm |
*depending on sample material and instrument configuration
Detection of Illegal Drugs and Pharmaceuticals
The detection of illegal pharmaceuticals and drugs is crucial in fields such as traffic, competitive sports, and forensic science.
It is possible to detect chemical substances in urine, saliva, hair, and blood. In fact, hair is known to store substances for a comparatively long period of time purely based on its length. Besides detecting drug abuse, hair samples are also useful in DNA analysis.
Need for Reproducible Sample Preparation
Based in Warrington, UK, Alpha Biolaboratories is a major provider of alcohol, illicit drugs, and DNA analysis. As the lab primarily conducts analyses on hair, it sought an optimized sample preparation process that can process more samples with a higher degree of reproducibility.
Ground hair has a larger contact area with the solvent than cut hair, which demonstrates enhanced drug extraction recovery and time. Additionally, the amount of cut hair required for ensuring representativity is also much higher.
Solution from RETSCH
Alpha Biolabs recognized that RETSCH’s mixer mill MM 400 had the potential to satisfy the requirements for efficient, repeatable sample preparation.
Since utilizing the mill, the lab has seen improvements in terms of both sample reproducibility and throughput. The equipment is used to concurrently prepare up to 20 hair samples in 2 ml plastic reaction vials, each containing two 6 mm balls.
Figure 2. Hair sample before pulverization
Image Credit: RETSCH GmbH
Figure 3. Hair sample after pulverization
Image Credit: RETSCH GmbH
Based on the hair sample’s fat content, liquid nitrogen may frequently be utilized as a grinding aid to stop the material from caking or sticking to the grinding jar walls. The RETSCH CryoMill with an integrated cooling system is the ideal solution for this application, as it is incredibly safe to handle and highly efficient.
An alternative option is cooling the sample externally, using the RETSCH CryoKit, for example, after the sample has undergone grinding in the MM 400.
Figure 4. The RETSCH CryoMill. Image Credit: RETSCH GmbH
Conclusion
RETSCH mixer mills are appropriate instruments that prepare hair samples quickly and with improved homogeneity and fineness. This, in turn, accelerates the extraction process and produces accurate and reliable analysis results.
Acknowledgments
Produced from materials originally provided by RETSCH GmbH.
About RETSCH GmbH
With more than 100 years of experience in sample preparation, RETSCH is the world’s leading manufacturer of instruments for homogenizing laboratory samples for analysis as well as for analyzing the particle size of solid substances by test sieving.
The RETSCH product portfolio includes a great variety of mills and jaw crushers, capable of reducing materials down to any required fineness, sieve shakers and test sieves as well as assisting technologies to optimize the handling of samples.
RETSCH instruments stand for representative sample preparation in compliance with relevant standards and contamination-free comminution processes – they are essential tools for preparing samples for laboratory analysis and stand for reliability, precision and durability.
Since 1990 RETSCH is part of the continuously growing technology group VERDER and forms the core of the group’s Laboratory Division VERDER SCIENTIFIC. Other companies belonging to this division are Retsch Technology GmbH, ATM GmbH, Eltra GmbH and Carbolite Gero Ltd.