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  • 1
    Electronic Resource
    Electronic Resource
    The production of powdered candidate biological and environmental reference materials in the laboratories of the Joint Research Centre (1998)
    Springer
    Fresenius' journal of analytical chemistry 360 (1998), S. 299-303 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The production of candidate biological and environmental reference materials in the laboratories of the Joint Research Centre, mainly on behalf of BCR, started in 1972 in Ispra and became concentrated in 1984 in Geel. Today, dedicated facilities for the transformation of biological and solid or liquid materials into dry powder samples are in use. The major guidelines followed in the conception of these facilities are described. Some typical examples of facilities developed or adapted to fulfil the specific requirements of professional CRM preparation are discussed, e.g. the whole-Teflon cryo-grinding equipment, the in-line controlled freeze-drier, the special facility for clean and dry handling of powders, the milling with classification equipment and the automation of bottling and labelling operations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050697
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  • 2
    Electronic Resource
    Electronic Resource
    The preparation of a certified reference material of polar pesticides in freeze-dried water (CRM 606) (1999)
    Springer
    Fresenius' journal of analytical chemistry 363 (1999), S. 632-640 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The preparation of a certified reference material of polar pesticides in freeze-dried water is described. The pesticides selected were atrazine, simazine, carbaryl, propanil, linuron, fenamiphos and permethrin which were added to 6000 litres of tap water at 50–80 μg · L–1 (200–320 μg · L–1 for permethrin) level in presence of NaCl (2.5 g · L–1) prior lyophilization. After the freeze-drying process the residue was rehomogenized, filled into amber glass bottles and stored at –20 °C, +4 °C and +20 °C. All pesticides were determined by HPLC/diode array detector, except permethrin which was determined by GC/ECD. The results obtained for atrazine, simazine, carbaryl, propanil, linuron and fenamiphos showed no within- or between-bottle inhomogeneity, however the material was non-homogeneous for permethrin and therefore this was withdrawn from further studies. With respect to the stability for over one year, all pesticides were stable at –20 °C. At +4 °C all pesticides were stable for at least 9 months and at +20 °C the stability was demonstrated only during the first month of storage. The content (mass fractions) of atrazine, simazine, carbaryl, propanil and linuron in freeze-dried water (CRM 606) was certified by an interlaboratory testing and a certification campaign.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160051263
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  • 3
    Electronic Resource
    Electronic Resource
    A pilot study for the preparation of a new Reference Material based on antarctic krill (1998)
    Springer
    Fresenius' journal of analytical chemistry 360 (1998), S. 410-414 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The preparation of new Certified Reference Materials (CRMs) of antarctic matrices forms the backbone of an ongoing project in the framework of the Italian National Program for Antarctic Research. The first CRM of this kind (MURST-ISS-A1 Antarctic Marine Sediment) is already available. The second phase focuses on the certification of antarctic krill, a small shrimp extremely abundant in the Southern Ocean. The total mass of krill available for this purpose is approximately 44 kg and results from the combination of three different catches (Ross Sea, Marguerite Bay and Livingston Island, respectively). The quantification of the following elements in the raw mass appears to be affordable by current analytical techniques, values being in the range of (in μg/g) 0.11–0.30 for As, 0.03–0.12 for Cd, 0.06–0.23 for Cr, 6.1–21 for Cu, 5.7–7.6 for Fe, 0.005–0.008 for Hg, 0.7–1.2 for Mn, 0.013– 0.077 for Ni, 0.04–0.57 for Pb and 12–16 for Zn. On the other hand, the average values ascertained in freeze-dried krill are as a rule one order of magnitude higher, i.e., (in μg/g), 3.2 for As, 0.6 for Cd, 1.8 for Cr, 75 for Cu, 61 for Fe, 0.025 for Hg, 4.6 for Mn, 0.7 for Ni, 2.1 for Pb and 81 for Zn. Information on the pretreatment of krill and details on the planned certification campaign are also given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050724
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  • 4
    Electronic Resource
    Electronic Resource
    Certification of the contents of five polychlorodibenzo-p-dioxins and six polychlorodibenzo furans in milk powder (1997)
    Springer
    Fresenius' journal of analytical chemistry 359 (1997), S. 222-229 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract  Preparation, homogeneity and stability studies of a natural milk powder material and subsequent certification of the mass fraction of five polychlorodi-benzo-p-dioxins (D48, D54, D66, D67, D70) and six polychlorodibenzo furans (F83, F94, F114, F118, F121, F130) are described. The material, CRM 607, is intended for use in the method validation and quality control of the complete analytical procedure for congener-specific determination of dioxins in milk powder and similar dairy products and was certified in an interlaboratory study for: 2,3,7,8-TCDD, 0.25 ng/kg; 1,2,3,7,8-PeCDD, 0.79 ng/kg; 1,2,3,4,7,8-HxCDD 0.42 ng/kg; 1,2,3,6,7,8-HxCDD, 0.98 ng/kg; 1,2,3,7,8,9-HxCDD, 0.34 ng/kg; 2,3,7,8-TCDF, 0.05 ng/kg; 1,2,3, 7,8-PeCDF, 0.054 ng/kg; 2,3,4,7,8-PeCDF, 1.81 ng/kg; 1,2,3,4,7, 8-HxCDF, 0.94 ng/kg; 1,2,3,6,7,8-HxCDF, 1.01 ng/kg and 2,3,4,6,7,8-HxCDF, 1.07 ng/kg. An indicative (non-certified) value was assigned to the mass fraction of the hepta- and octachlorinated congeners D73, D75, F131, F134, F135 and the HxCDF F124.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050564
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  • 5
    Electronic Resource
    Electronic Resource
    Comparison of some additives used in the preparation of freeze-dried lemon juice candidate reference materials (1998)
    Springer
    Fresenius' journal of analytical chemistry 360 (1998), S. 445-448 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The stability, storage, and distribution of certified reference materials which consist of liquid or frozen fruit juices is rather problematic. As a better alternative a stable orange juice powder has been obtained by freeze-drying to a moisture content below 0.4%. However, freeze-drying lemon juices resulted in unstable materials which collapsed into lumps after standing some weeks in brown bottles under argon. An additive was sought which can be used to obtain stable lemon juice powders without influence on important analytical parameters as amino acids, sugars, organic acids, minerals and flavanone glycosides. The additives pectin, hydroxy ethylcellulose, and hydroxypropyl methylcellulose were examined. Powders containing pectin quickly showed a loss of structure (collapse) and resulted in non-acceptable changes in amino acids, sugars or minerals compared to the original lemon juice. The addition of up to 3% hydroxypropyl methylcellulose seemed more promising, although some minor changes in the sugar and sodium concentration occurred.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050734
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  • 6
    Electronic Resource
    Electronic Resource
    Planning and certification of new multielemental reference materials for research in antarctica (1996)
    Springer
    Microchimica acta 123 (1996), S. 119-128 
    Details
    ISSN: 1436-5073
    Keywords: environmental contamination ; Antarctic ocean water ; Antarctic marine sediment ; krill ; certified reference materials for research in Antarctica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The adoption of the principles of Good Laboratory Practice (GLP) and the implementation of the ensuing procedures for quality assurance (QA) and quality control (QC) of analytical determinations are nowadays deemed essential to the achievement of sound, credible and comparable experimental information. This is certainly also applicable to research projects currently being carried out in the antarctic continent, in particular as regards investigations on global change phenomena. Worldwide investments made so far in this field do require in fact that reliability of data be optimized so as to allow for a harmonized assessment of ongoing trends. In this context the Italian National Programme for Research in Antarctica has recently launched a project for the preparation of new multielemental certified reference materials (CRMs) to be used for QC of analyses performed on environmentally significant materials. The suitability of CRMs to verify the accuracy of experimental measurements acknowledgedly depends, among others, on the degree of similarity of their matrix composition and analyte levels to those expected for real samples. From this standpoint three CRMs are planned, namely: i) marine sediment certified for Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sn and Zn; ii) ocean water certified for Cd, Cr, Cu, Fe, Hg, Mn, Ni and Pb; iii) krill certified for As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sn and Zn. Regarding the first two matrices, amounts of ca. 100 kg and ca. 1001, respectively, have been collected during the IX (1993–1994) antarctic expedition, while krill was taken in the course of the X (1994–1995) campaign. The pretreatment of sediment has been accomplished in terms of homogenization, stabilization and characterization of the preliminary ground mass. Approximately 500 bottles, each containing 75 g of material are now ready for distribution to interested laboratories involved in chemical measurements of antarctic matrices, whereas ocean water and krill will follow at a later stage. Finally, depending on circumstances, also the certification of organochlorine compounds in the same materials will be attempted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01244385
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  • 7
    Electronic Resource
    Electronic Resource
    Certification of the mass fractions of Ca, Cu, Cl, I, Fe, K, Mg, P, Pb, N, Na and Zn in skim milk powder (1994)
    Springer
    Microchimica acta 113 (1994), S. 381-394 
    Details
    ISSN: 1436-5073
    Keywords: certified reference material ; skim milk powder ; analytical quality control ; major constituents ; trace elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Analyses of milk and milk products are routinely performed by a number of dairy laboratories to control the quality of these products with regard to e.g. nutritional components and potential exposure to toxic elements. In order to improve and control the quality of such analyses the Community Bureau of Reference (BCR) has organized series of certification campaigns to produce reference material of milk certified for a variety of elements and compounds. The increasing demand is such that the stock of some of these materials is now exhausted. Consequently, the BCR decided to produce a new batch of CRM of skim milk powder certified for its contents of Ca, Cu, Cl, I, Fe, K, Mg, P, Pb, N, Na and Zn (CRM 063R). This material was carefully prepared (spray-drying) and its homogeneity and long term stability was verified. This paper presents the certification work performed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01243627
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  • 8
    Electronic Resource
    Electronic Resource
    BCR (non-certified) reference materials for dioxins and furans in milk powder (1995)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 352 (1995), S. 179-183 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Milk powders spiked with different quantities of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) have been prepared by both freeze drying and spray drying. In 1991, the freeze dried batches were used in a BCR intercomparison. The spray dried batches have now been compared to the freeze dried ones. The obtained results show that: -there is no significant difference between the materials; -the recoveries of the added amounts of D48, D54, D66, D67, D70, F83, F94, F114, F118, F121 and F130 are of the order of 90%. On this basis, assigned values are proposed for the spray dried materials which will become available as a set of three (non-certified) BCR reference materials (RM 532, RM 533, RM 534).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00322321
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  • 9
    Electronic Resource
    Electronic Resource
    Comparison of methods used for the preparation of biological CRM's (1995)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 352 (1995), S. 125-130 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The starting material for two certified and one candidate reference material was obtained from dried grass specially cultivated on a selected and well prepared soil. The Community Bureau of Reference (BCR) of the Commission of the European Communities produced two certified reference materials (CRM's) from this dried grass: a rye grass material (CRM 281) certified in 1988 for the quality control of trace and toxic element analyses and a hay powder material (CRM 129) certified in 1989 for monitoring trace and minor elements. A fraction of the dried grass was used in 1993 for the preparation of a hay powder with a particle size of 〈63 μm using newly developed grinding techniques. This paper compares the production methods of these three materials and the obtained particle size distribution of the powders. The analytical evaluation of these production methods was carried out by solid sampling Zeeman atomic absorption spectrometry for the determination of Cd, Pb and Zn.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00322311
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  • 10
    Electronic Resource
    Electronic Resource
    The development of cryo-grinding equipment for the transformation of large quantities of biological reference materials with low heavy metal contents (1990)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 338 (1990), S. 390-393 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Conventional devices used for crushing or grinding of large quantities (up to 200 kg) of biological reference materials to be certified for trace metals can cause severe and heterogeneous contaminations by metals as well as losses of trace elements by excessive heat generation. In such cases cryogenic processing and homogenisation is a useful technique, but in general it has been used only for relatively small quantities. This paper describes the development of equipment with a production capacity of 3 kg/h, and its use for the production of a BCR codfish RM. It consists of: 1. A laboratory jaw crusher in which all parts in contact with the material to be processed are made of teflon or KELF. During the crushing process both the crushing chamber and the material are continuously cooled below the brittle point using liquid nitrogen. 2. The enlarging of a commercial planetary ball mill with bowls and balls made of teflon, which are cooled using liquid nitrogen to temperatures below −60°C during operation. The optimisation of parameters such as the number of balls and their diameter, amount of material per bowl, cooling time, rotation speed and milling time are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00322501
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