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Journal des Clients "l'échantillon" (1)

  • No. 43

    Analyses alimentaires - préparation d’échantillons reproductible avec les broyeurs de laboratoire RETSCH

Rapport de tests (46)

  • 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.
  • Die neue Power Generation

    Planeten-Kugelmühlen haben seit jeher einen festen Platz in der täglichen Laborpraxis zur Feinzerkleinerung unterschiedlichster Materialien. Neben dem Mischen und Zerkleinern hat sich in den letzten Jahren auch im mechanischen Legieren z.B. thermoelektrischer oder hochkoerzitiver Materialien ein weiteres Anwendungsgebiet ergeben.
  • Effektive Zerkleinerung mit Schlagrotormühlen

    Die reproduzierbare und kontaminationsneutrale Probenaufbereitung spielt eine entscheidende Rolle im Hinblick auf zuverlässige Analysenergebnisse. Ein wichtiger Schritt ist die Homogenisierung und Zerkleinerung der Probe auf eine definierte Feinheit mit Hilfe von Labormühlen. Neben der Zerkleinerung auf Analysenfeinheit können die Schlagrotormühlen von Retsch auch für die Kleinproduktion, Herstellung von Musterchargen und in der Forschung und Entwicklung von neuen Produkten eingesetzt werden.
  • Komplexe Lebensmittelproben schnell und reproduzierbar zerkleinern

    Nahrungsmittel treten in sehr unterschiedlichen Formen und Konsistenzen auf und sind i.d.R. inhomogen. Für die Analytik z.B. zur Bestimmung von Nährwerten oder zum Auffinden von Schadstoffen werden jedoch homogene und repräsentative Proben benötigt, um aussagekräftige und reproduzierbare Ergebnisse zu erhalten. Im Rahmen der Probenvorbereitung müssen die oft sehr komplexen Proben homogenisiert und auf eine hinreichende Partikelgröße zerkleinert werden. Ideale Helfer bei diesem wichtigen Schritt sind Labormühlen unterschiedlicher Bauart, wie sie von RETSCH angeboten werden.
  • 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.
  • 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 Futtermitteln für die NIR Analytik

    In der Haltung von Nutztieren hat die Qualität der Futtermittel einen bedeutenden Einfluss auf die Produktivität. Darüber hinaus bringt Tiernahrung die am stärksten schwankenden Kosten, die mit der Haltung von Nutztieren verbunden sind, mit sich. Deshalb ist eine zuverlässige Analyse von Futtermitteln und Futterinhaltsstoffen der beste Weg, ein ausgewogenes Fütterungsprogramm zu gewährleisten und gleichzeitig die Wirtschaftlichkeit des Betriebs zu optimieren.
    Die Nah-Infrarot-Spektroskopie ist die wichtigste Analysenmethoden bei Futtermitteln zur Bestimmung von Daten wie Proteingehalt, Feuchte, Fett und Asche. Der Vorteil gegenüber klassischen Methoden wie z.B. Kjeldahl ist, dass mehrere Parameter gleichzeitig bestimmt werden können. Außerdem ist die NIR-Spektroskopie ein schnelles Verfahren, das kein Verbrauchsmaterial und keine Reagenzien benötigt. Deshalb wird sie immer dort eingesetzt, wo ein hoher Probendurchsatz und eine große Flexibilität erforderlich sind. Die Identifizierung und Qualifizierung der Rohstoffe sowie die quantitative Analyse von Fertigprodukten können innerhalb weniger Sekunden durchgeführt werden, um höchste Produktqualität und -sicherheit zu gewährleisten.
    Eine viel diskutierte Frage im Zusammenhang mit der NIR-Spektroskopie ist die Notwendigkeit der Probenvorbereitung. Der Anwender steht häufig vor dem Problem zu entscheiden, wann eine Probenvorbereitung erforderlich ist und wann nicht.
  • Schnell und schonend zerkleinern

    In zahlreichen Labors werden täglich viele unterschiedliche Probenmaterialien aufbereitet. Für die Zerkleinerung von Feststoffproben auf Analysenfeinheit wird eine Mühle benötigt, die nicht nur vielseitig einsetzbar und leicht zu reinigen ist, sondern die auch eine reproduzierbare Probenvorbereitung – und damit zuverlässige Analysenergebnisse - garantiert.
    Mit der Ultra-Zentrifugalmühle ZM 200 bietet RETSCH eine Rotormühle an, die nicht nur sehr schnell, sondern auch äußerst materialschonend zerkleinert und, dank einer umfangreichen Zubehörpalette, universell einsetzbar ist. Mit ihrem kraftvollen Powerdrive-Antrieb vermahlt die ZM 200 weiche bis mittelharte und faserige Materialien extrem schnell auf Endfeinheiten bis unter 100 µm und steigert so den Probendurchsatz im Labor.
  • Staub stört - Wareneingangskontrolle von Getreideflocken mittels Siebanalyse

    Lebensgarten aus dem vogtländischen Adorf ist ein Hersteller von ökologisch und nachhaltig produzierten Backwaren, Müslis und Schokoladenartikeln. Um die Qualität der Endprodukte zu sichern, werden die angelieferten Getreideflocken auf ihren Staubund Feinanteil überprüft. Hier erfahren Sie wie dieses Prüfverfahren funktioniert und welche Rolle in ihm die Vibrationssiebmaschine AS 200 control von Retsch spielt.
  • Vermahlungen ohne Verlust von Inhaltsstoffen

    Kryomühle im Einsatz an der BTU Cottbus
    Bei vielen Materialien ist es vorteilhaft eine Kryomühle für die Zerkleinerung einzusetzen, statt einer Labormühle, die bei Raumtemperatur arbeitet. Die Probe wird durch den eingesetzten flüssigen Stickstoff versprödet und kann darum besser durch Schlag, Druck und Reibung zerkleinert werden; außerdem bleiben leicht flüchtige Bestandteile erhalten. An der Brandenburgischen Technischen Universität (BTU) Cottbus ist eine Kryomühle in den Bereichen Kunststoffrecycling und Biomaterialien im Einsatz.
  • 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.
  • 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.
  • Cold, sticky and tough - Cryogenic grinding improves breaking properties

    Sticky, tough or elastic samples are generally difficult to pulverize. Cheese, for example, can be ground with a knife mill but only to a final fineness of about 1 – 2 mm which is not small enough for most analysis techniques. Sweets, on the other hand, often consist of various components like elastic foamy sugar with a sticky, liquid filling. If these types of sample are not embrittled before grinding, they tend to clog the mill. Cryogenic treatment, however, improves the breaking properties of cheese or candy so that even elastic materials can be successfully pulverized.
  • CryoMill - Cryogenic grinding was never more convenient or efficient

    Some sample materials have properties which make size reduction at ambient temperature impossible. If, for example, very elastic materials need to be ground or volatile components have to be preserved for further analysis, it is essential to carry out cryogenic grinding. The use of liquid nitrogen helps to embrittle the sample, thus improving its breaking properties, and preventing volatile substances from escaping due to the frictional heat produced by the grinding process.
  • 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.
  • Detection of Mycotoxins in Nuts

    Preliminary and fine size reduction
  • Detection of genetically modified organisms (GMO) in food and feed

    Genetic engineering opens up new possibilities in areas such as medical research, development of alternative fuels or global food supply. It is used to modify the characteristics of plants in order to increase the crop yield, improve defense against predators, pesticides or draught, but also increase concentrations of essential vitamins. However, with regards to food the use of genetic engineering is a fairly controversial issue. Moreover, food and feed stuff are subject to rigorous quality control processes to prevent humans and animals from potential harm.
  • Efficient Grinding at –196 °C

    RETSCH’s New CryoMill for Safe and Reproducible Grinding with Liquid Nitrogen
  • 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.
  • 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 differences in the quality.
  • From muesli to streaky bacon - Complete homogenization of complex samples

    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 the sample preparation of food. The model GM 200 has proven itself for the homogenization of small sample volumes of up to 700 ml. For larger volumes RETSCH offers the GM 300 model with a grinding chamber volume of 5,000 ml.
  • How to minimize standard deviations by correct sample preparation

    Modern analytical methods increase precision and push detection limits to make even the smallest traces of sample components detectable. Despite this development sample preparation, which is carried out prior to the actual analysis, is frequently neglected. Errors caused by lacking accuracy in sample preparation have a much bigger impact than errors made during analysis. Just like an iceberg which is mostly hidden under water, only a small part of the sum of errors is perceived whereas the major part of potential errors is not taken into account (fig. 1). One of the reasons may be the fact that sampling and sample preparation have always been done in a traditional way which has become a routine over the years and is no longer considered as having a critical influence on the subsequent analyses.
  • Measuring Dust - Incoming Inspection with Sieve Analysis

    Graduate student Jennifer Franz has developed a new inspection procedure during her work at the German food producer Lebensgarten GmbH. With the help of sieve analysis the company can now reliably ascertain the fines and dust fractions of incoming cereal flakes; these have a negative influence on the mixing and packaging process of muesli.
  • New Knife Mill Sets Standards

    The so-called QuEChERS method (“quick, easy, cheap, effective, rugged and safe”) has been developed to make sample preparation to pesticide analysis more efficient. Serial tests have proved that the analysis results obtained with the QuEChERS method can easily bear comparison with more common methods, such as DFG S19. To guarantee reproducible analysis results, it is essential to completely homogenize the sample. To make sure the sample preparation is reproducible, the homogenization process needs to be carried out with a laboratory mill.
  • Particle size - a quality feature

    The determination of the particle size distribution of a product has always been of great significance in food production. Taste, color, solubility or extraction behavior are only a few examples of product properties which are directly influenced by particle size. Traditionally, analytical test sieving provides a quick and simple possibility to characterize the particle size of bulk goods. In the testing laboratory of the St. Petersburg branch of LLC Wrigley RETSCH sieve shakers AS 200 jet and AS 200 control are utilized for particle size analysis of fine powders which are used for chewing gum production.
  • 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.
  • 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.
  • Quick and reproducible grinding of feedstuff

    Grain, compound feeds or feed pellets occur in a variety of forms; compound feeds are usually inhomogeneous. Feedstuff is analyzed, for example, to determine the nutritional value, to detect hazardous substances or genetically modified ingredients. To ensure meaningful and reliable analysis results, representative and homogeneous samples are required. Therefore, sample preparation involves homogenization and size reduction of the material to a defined particle size. RETSCH laboratory mills are perfectly suited for this process.
  • Reliable sample preparation in food technology

    An efficient sample preparation procedure for rapid, reliable and reproducible analytical results is becoming increasingly important today. Ever more stringent requirements are being set both in research and production, e.g. for product monitoring and quality control.
  • 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.
  • 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.
  • Sample Division of Large Volumes

    Representative sampling of large sample volumes is an integral part of the physical and chemical analysis of bulk goods and has a decisive influence on the quality of the results. Extraction of a sample from the bulk is not always carried out in a way to ensure representativeness. This is a widespread flaw in the quality control process with a negative impact on the subsequent analysis results. Therefore, more attention should be paid to the correct sampling procedure. Sample division is often considered as a labor-intensive process which not always leads to representative results. RETSCH provides some convenient solutions which help to improve working conditions and thereby the quality of the sampling process.
  • 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 for pesticide residue analysis with the QuEChERS method

    The so-called QuEChERS method (“quick, easy, cheap, effective, rugged and safe”) was developed by Michelangelo Anastassiades (Chemical and Veterinary Investigation Office CVUA, Stuttgart, Germany) to make sample preparation to pesticide residue analysis more efficient. It basically consists of three steps: Homogenization – Extraction – Analysis. Test series have proved that the analysis results obtained with the QuEChERS method can easily compare with more common methods, such as DFG S19. Various RETSCH instruments are used for the sample preparation process.
  • Sample preparation of feeds and forage for NIR analysis

    The feed quality has a decisive influence on the productivity of livestock farming. However,  high-quality forage considerably adds to the costs of stock breeding. Consequently, economic considerations focus on the quality and quantity of the components used in the production process. This includes reliable analyses of feedstuff and ingredients from receipt of goods to final inspection as the best way to ensure a balanced feeding of the animals while keeping cost and profit orientation in focus.
    Near Infrared Spectroscopy (NIR) 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.
  • Sample preparation of feeds and forage for NIR analysis

    Als Standard Analysenmethode für den Gehalt an Protein, Fett, Kohlenhydrat und Feuchte kommt in der Futtermittelindustrie vor allem die Nah-Infrarot (NIR) Spektroskopie zum Einsatz. Der labortechnische Aufwand für die Probenvorbereitung und  Messung mit dem NIR-Verfahren ist vergleichsweise gering. Entsprechend weit verbreitet ist das Prüfverfahren. Die empfindliche spektroskopische Technik setzt voraus, dass die zu analysierende Probe repräsentativ ist, eine ausreichende Analysenfeinheit besitzt und eine möglichst hohe Homogenität aufweist. Hierdurch werden Messartefakte verhindert bzw. auf ein Minimum reduziert.
  • Sieving of agglomerating powders with the air jet sieving machine AS 200 jet

    Air jet sieving is usually the method of choice for dry sieving of materials with particle sizes below 40 microns. However, it is also a faster alternative to vibratory sieving of materials of up to 250 microns.
  • 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.
  • Tracing poison - Sample preparation for analysis of toxic elements

    Reports on findings of hazardous substances in food products are nothing unusual these days: pesticides in fruit, arsenic in rice or toxic plant parts in tea, to name but a few. Therefore, permanent quality control is an indispensable tool of consumer protection. Apart from the actual food testing, sample preparation by homogenization is essential to obtain reliable results.
  • 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.
  • What's in the fish - Effective size reduction by cutting

    The homogenization of fish is a challenge; scales, skin and bones are fairly resistant to size reduction so that the sample still contains some larger pieces after grinding in most mills. A high fat content of the fish makes the process even more difficult, as fatty particles stick together to form large lumps which block the mill and keep the sample inhomogeneous.
  • White Paper: Cryogenic Preparation of Sample Materials

    A solid sample material should always be sufficiently prepared by size reduction and homogenization before it is subjected to chemical or physical analysis. Care should be taken that the analysis sample fully represents the original material and that the sample preparation process is carried out reproducibly. Only then are meaningful results guaranteed. Most sample materials can be reduced to the required analytical fineness at room temperature by choosing a mill with a suitable size reduction principle (impact, pressure, friction, shearing, cutting).
  • White gold - Grinding large sample volumes

    Rock salt and sea salt not only consist of sodium chloride but may also contain other minerals and silicates, depending on the mining area and method. To analyze the composition of salt, the sample needs to be sufficiently homogenized, considering that larger lumps of rock salt are usually very inhomogeneous. The element concentrations in salt are usually very low so that it is frequently necessary to process amounts in the kilogram range. The Rotor Beater Mill SR 300 easily pulverizes charges of several kilogram and is therefore ideally suited for this application.

Témoignages (7)

Rapports d'essais (115)