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Aplikace/Zaměření  leták (4)

Zákaznický časopis „the sample“ (9)

No. 36
Umění mletí - Moderní technologie mletí
No. 35
NEW PRODUCTS TRIED AND TESTED
No. 34
NOVÉ PRODUKTY'10
No. 33
SAMPLE PREPARATION IN PRACTICE & NEW RETSCH INSTRUMENTS
No. 32
SAMPLE PREPARATION for Instrumental Analysis
No. 31
Grand Prix Season 2008 & New RETSCH Instruments
No. 30
Mills and Particle Analyzers for Environmental Analysis
No. 29
New Product Generation 2007
No. 28
Think big but grind fine!

Technické zprávy (29)

Representative Analysis Results Require Adequate Sample Preparation
A faultless and comparable analysis is closely linked to an accurate sample handling. Only a sample representative of the initial material can provide meaningful analysis results. Rotating dividers and rotary tube dividers are an important means to ensure the representativeness of a sample and thus the reproducibility of the analysis. Correct sample handling consequently minimizes the probability of a production stop due to incorrect analysis results. Thus correct sample handling is the key to effective quality control.
Sample Preparation and Analysis of Arsenic in Rice
Considerable care must be taken when analyzing a sample like rice in order to achieve an accurate result. The major source of error when analyzing a bulk material comes not from the analytical measurement itself, but from the sample handling, i.e., sampling, sample division, grinding, digestion, etc.
Sample Preparation of Feeds and Forage for NIR Analysis
Near Infrared Spectroscopy is the most important analytical method for the determination of protein content, moisture, fat and ash in feeds and forage. The advantage over classical methods such as Kjeldahl is the simultaneous determination of several parameters. Moreover, NIR spectroscopy is a quick method which requires neither consumables nor reagents. Therefore it is used whenever high sample throughput and great flexibility are required. The identification and qualification of raw materials as well as the quantitative analysis of convenience products can be carried out within seconds to guarantee highest product quality and safety.
A much discussed issue related to NIR analysis is the necessity of sample preparation. Users often face the problem of having to decide whether sample preparation is required or not.
Renewable energies on the rise
Sample preparation of vegetable-based raw materials with laboratory mills

Thanks to the increasing usage of biomass as a source of energy, the analysis of these materials in the context of R&D and quality control gains importance, too. Due to the complex properties of plant materials, adequate sample preparation can be rather a challenge.
Representative results require adequate sample preparation
The following situation is typical for many production plants: After a routine quality check, the production process is stopped or an already produced batch is suspended, because the analysis results were not within the relevant critical values. But does the tested product really deviate from the specifications? The quality control managers are convinced of this because modern analysis instruments provide results with very low tolerances. The sample in question was tested several times and the result was confirmed. The question is why the product does not match the specifications although the production parameters have not been changed in any way.
The possibility that the tested product is indeed deficient cannot be excluded. However, it is often not the product itself which causes irregular analysis results but a lack of understanding of the steps which come before the analysis.
Powerful Cutting Mill
The SM 300 excels especially in the tough jobs where other cutting mills fail. It has a freely selectable speed range from 700 to 3,000 rpm with high torque. The mill is convenient to operate and easy to clean. Reliable and extremely efficient sample preparation in the laboratory is now guaranteed with the SM 300.
Renewable energy
Wood residues from forestry work and wood processing are usually processed to wood chips. These can be used in different ways, depending on the type of wood, bark and residual moisture, for example as raw material for chipboards or as substrate for the cultivation of mushrooms. The major part, however, is used for energy generation. The quality of the wood chips can vary significantly, depending on their origin and condition. Trade and industry are interested in the percentage of dry matter and in the calorific value of the chips as the price calculation depends on the water contents of the product. With the analysis result representing an important economic factor, the representative and reproducible sample preparation gains importance, too.
Are cereal bars really healthy?
Food manufacturers often promote their products as „light“ or, such as in the case of cereal bars, „healthy“. If that is actually true, can only be verified by analyzing the nutritional values, a procedure which forms an important part of food quality control. The values of fat, saturated fatty acids, sugar and salt which are printed on the packaging represent an average of the content of each substance and relate to 100 ml respectively 100 g of the product. The cereal bars consist of a heterogeneous mixture of ingredients (nuts, raisins, oat flakes etc.), therefore the thorough homogenization of the sample is required to obtain meaningful analysis results.
Air Jet Sieving of Bulk Materials
Particle size analysis and particle size distribution are important criteria for the quality  control of bulk materials. In a running production process, the results of a quality check must be available quickly to allow for immediate adjustment of the production parameters. Depending on the expected particle size and sample volume, different sieving methods and sieving machines are suitable for analysis. The method used for particle size analysis is primarily determined by the fineness of the material to be sieved. For dry sieving of samples with particle sizes below 40 microns, air jet sieving is the method of choice.
From cacao tree to chocolate bar
The way from the cacao tree to the chocolate bar is a long one. Due to the many processing stages – harvest, fermentation, drying, cleaning, roasting, pre-crushing and finally grinding the cocoa nibs to liquor from which cocoa powder and cocoa butter are pressed – there may be significant variations in the quality. The quality control process not only includes testing the innocuousness of the product (e. g. fungi, heavy metal contamination) or the ingredients (fat, carbohydrate content), it also involves size reduction to an adequate particle size for a sensory test of the cocoa liquor. That is important because the human palate perceives particles as small as 30 microns as unpleasant.
Perfect Homogenization with the GRINDOMIX GM 300
The diversity of foodstuffs with their often very different product properties represents a real challenge for food testing laboratories. Before the actual analysis, the sample materials – which can vary strongly with regards to hardness and moisture – need to be homogenized and reduced to a sufficiently small particle size. RETSCH’s GRINDOMIX knife mills are the ideal tools to meet the complex requirements of sample preparation of food. The model GM 200 has proven itself for the homogenization of smaller sample volumes of up to 700 ml. For larger volumes RETSCH now offers the new GRINDOMIX GM 300 with a grinding chamber volume of 5,000 ml.
Using the CryoMill for samples with volatile substances
For the size reduction of many materials it is more suitable to use a cryogenic mill than a laboratory mill which operates at room temperature. The sample is embrittled by liquid nitrogen which improves its breaking behavior when submitted to impact, pressure and friction; moreover, volatile components of the sample are preserved. The RETSCH CryoMill is not only the most modern and safest cryogenic mill in the market, it also provides excellent grinding results.
Cutting Mill SM 300 - Refinement of a well-proven grinding principle
Cutting mills are used in many different areas of sample preparation for subsequent analyses. Typical applications include the size reduction of secondary fuels, the processing of biomass for renewable energy research, the control of products in the context of RoHS and WEEE regulations or the recovery of precious metals – the variety of sample materials is huge.
Renewable raw materials are gaining ground
The representative sample preparation of plants requires experience
Toxic analyses of biological samples
Cryogenic grinding facilitates the preparation of animal samples
Detection of Mycotoxins in Nuts
Preliminary and fine size reduction
Fat Analysis in Food and Feed
Size reduction of samples with a high fat content
Efficient Grinding at –196 °C
RETSCH’s New CryoMill for Safe and Reproducible Grinding with Liquid Nitrogen
Milling of Samples in a Fertilizer Laboratory
The fertilizer laboratory of the Division of Regulatory Services at the University of Kentucky uses the Retsch ZM 200 ultra centrifugal mill for milling fertilizer samples.
Preparation of Soil, Sewage Sludge and Sediment Samples in a Wastewater Treatment Laboratory
The preparation of a mixture of organic and inorganic samples holds some difficulties: whereas sand, clay and stones can usually be ground to homogeneous samples with suitable laboratory mills, the high energy input can cause samples with organic components such as fat or starch to cake. Carsten Bunn, a laboratory technician at the waste water treatment laboratory BRW, has to deal with this problem every day. He treats samples which are taken from the sand traps of the wastewater treatment plants and consist of exactly that mixture. The sediments of household and industry waste water not only contain sand, clay or leaves but anything that people nowadays dispose of through the sewer system: cellulose, hair and especially food residues.
Size reduction within the context of sample preparation
In general “size reduction” is taken to mean the disintegration of solid substances by mechanical forces without altering their state.
Fettbestimmung in Lebens- und Futtermitteln
Methoden und Vorgehen
Höchstleistung im Doppelpack
Mit der PM 100 und der PM 200 präsentiert Retsch eine neue Generation von Planeten-Kugelmühlen mit einer bzw. zwei Mahlstellen, die in diesem Produktsegment neue Leistungsstandards setzen.
Komplexe Proben homogenisieren
Messermühlen zur professionellen Probenvorbereitung im Labor

Nahrungsmittel treten in sehr unterschiedlichen Formen und Konsistenzen auf und sind i. d. R. inhomogen. Für die Analytik werden jedoch homogene und repräsentative Proben benötigt, um aussagekräftige Ergebnisse zu erzielen. Im Rahmen der Probenvorbereitung müssen die oft sehr komplexen Proben also homogenisiert und auf eine hinreichende Partikelgröße zerkleinert werden. Dabei können die Materialien sehr stark in Bezug auf Härte und Feuchte variieren. Um den vielschichtigen Anforderungen der Probenvorbereitung von Lebensmitteln gerecht zu werden, bietet sich der Einsatz von Messermühlen an.
Neue Messermühle setzt Standards
Die Messermühle GRINDOMIX GM 300 eignet sich für die schonende Zerkleinerung und Homogenisierung von Lebensmitteln. Sie kann Probenvolumina von bis zu 4,5 l schnell und reproduzierbar verarbeiten. Mit vier scharfen, robusten Klingen und einem leistungsstarken Motor mit bis zu 3 kW Spitzenleistung ist sie ideal ausgerüstet zur Homogenisierung von Substanzen mit hohem Wasser-, Öl- oder Fettanteil ebenso wie zur Zerkleinerung trockener, weicher, mittelharter und faseriger Produkte.
Perfekte Homogenisierung von Lebensmittelproben
Nahrungsmittel treten in sehr unterschiedlichen Formen und Konsistenzen auf und sind in der Regel inhomogen. Für die Analytik werden jedoch homogene und repräsentative Proben benötigt, um aussagekräftige Ergebnisse zu erzielen. Für diese Aufgabe sind die Messermühlen Grindomix GM 200 und GM 300 von RETSCH die idealen Instrumente.
Probenvorbereitung von Böden
Bestimmung von anorganischen Inhaltsstoffen in Bodenproben

In Industrienationen mit hoher Besiedlungsdichte und einem begrenzten Angebot an Industrie- und Gewerbegebieten unterliegt die Nutzung von Gebäuden und Flächen einem dauerhaften Wandel. Daher sind Bodenuntersuchungen für Investoren, Behörden und Privatpersonen unumgänglich. Umweltanalytische Untersuchungen bilden die Basis, um Gefährdungen aufzuzeigen und damit Menschen und eingesetztes Kapital zu schützen. Bei SGS Institut Fresenius in Herten werden bis zu 400 Bodenproben am Tag aufgearbeitet und analysiert. Hierbei wird sehr genau darauf geachtet, dass geltende Normen und Verordnungen eingehalten werden. In Deutschland gilt die BbodSchV, wobei die Analytik auch auf die Vorschriften anderer Länder angepasst wird.
Zerkleinern von Proben in einem Düngemittellabor
Für die genaue und reproduzierbare Analyse von Düngernährstoff, Spurennährstoffen und Spurenmineralien ist das vorherige Zerkleinern der Probe unverzichtbar. Das Düngerlabor der Division of Regulatory Services der University of Kentucky verwendet zum Homogenisieren der Proben die Ultra-Zentrifugalmühle ZM 200 von Retsch.
Molienda ultrarrápida y ultrafina
El nuevo molino ultracentrífugo ZM 200 de RETSCH es un molino de rotor no sólo extremadamente rápido y cuidadoso con el material molido, sino también de uso universal gracias a su amplia gama de accesorios.

Z tisku (3)

  • Cyclone Mills

  • Neue Zyklonmühle für die Probenvorbereitung zur NIR Analytik

    RETSCH hat die Zyklonmühle TWISTER speziell für die Probenvorbereitung von Lebens- und Futtermitteln entwickelt, die anschließend mittels NIR analysiert werden. Die optimierte Form des Rotors und des Mahlraums erzeugt einen Luftstrom, der das zerkleinerte Mahlgut durch den integrierten Zyklon in das Probengefäß überführt. Der Luftstrom verhindert gleichzeitig ein Erhitzen der Probe, so dass Feuchtigkeitsverluste vermieden werden. Die im Lieferumfang enthaltenen Siebe garantieren eine optimale Partikelgrößenverteilung, was eine Neukalibrierung des NIR-Spektrometers überflüssig macht. Die Rotorgeschwindigkeit ist in 3 Stufen einstellbar und lässt sich somit an die Anforderungen der Probe anpassen. Der Reinigungsaufwand ist beim TWISTER sehr gering, da die Probe praktisch vollständig aus dem Mahlraum ausgetragen wird. Diese neue Zyklonmühle in bewährter RETSCH-Qualität optimiert die reproduzierbare Probenvorbereitung für die NIR Analytik und ermöglicht somit aussagekräftige Analysenergebnisse.

  • Versatile Ultra Centrifugal Mill with New Cyclone

    RETSCH’s powerful and versatile ZM 200 offers the ultimate in performance and operating comfort. It is used for the rapid size reduction of soft to medium-hard and fibrous materials down to 40 microns. Because of the efficient size reduction technique and the comprehensive range of accessories the ZM 200 ensures the gentle preparation of analytical samples in a very short time.
    For applications which require an optimum air throughput (e. g. heat sensitive materials) or if larger sample volumes need to be processed, the use of a cyclone is recommended. RETSCH offers a re-designed cyclone with improved functionalities for collector volumes from 250 ml to 5 liters which adds to the ZM 200’s great flexibility.
    Thanks to the wide range of accessories with different rotors, ring sieves and collectors, the ZM 200 can be easily adapted to suit a wide range of applications such as, for example, heavy-metal-free grinding, size reduction of abrasive materials or processing small volumes up to 20 ml.

Osvědčení (4)

Testovací zprávy (54)