Authors:Eveline De Robertis, Gabriela F. Moreira, Raigna A. Silva, and Carlos A. Achete
for thermal behavior studies, since by the standard method for such determinations the major drawback is the time of analysis.
In this work, our intention is verify the thermal behavior of two standard referencematerials (SRM) using DSC, such
Quality initiatives, such as ISO16949, require the calibration of apparatus using certified and traceable referencematerials [ 1 ]. In calorimetry, standard methods and referencematerials exist for the
Authors:A. Świtaj-Zawadka, P. Konieczka, J. Biernat, Y. Takao, K. Mita, S. Komar, M. Wesołowski, A. Przyjazny, and J. Namieśnik
Reference materials are used in every laboratory
in order to assure the appropriate quality of analytical results. The production
of reference materials is not an easy task especially in the case of gaseous,
toxic and malodorous compounds. Thermal decomposition of immobilized compounds
is a convenient way for the generation of those kinds of mixtures. Temperature
is an important variable in this process. In this case, thermoanalytical techniques
(thermogravimetry and differential scanning calorimetry (TG-DSC)) and scanning
electron microscopy (SEM) were used for checking the temperature range which
had been previously determined using thermal desorber-gas chromatograph-flame
ionization detector (TD-GC-FID) system.
INAA results of 11 standard reference materials used in archaeometric investigations of pottery as well as in environmental analysis are presented. The values obtained for 24 elements are compared with the certificate values as well as with the analytical data of other investigators. The accuracy of analysis is discussed.
Authors:M. Freitas, F. Catarino, C. Branquinho, and C. Maguas
For preparation of a multielement lichen reference material for environmental studies, 25 kg of the epyphitic lichen Evernia prunastri (L.) Ach. was collected in unpolluted regions of Portugal. The lichen was removed from Cistus ladanifer and Quercus spp. The material was ground to a mesh size 125 m. The material homogeneity was evaluated by determining Na, K, Mn, Br, As, La and Sm on two samples of 100 mg taken at each of 20 locations of the bulk material; the locations were randomly chosen. The k0-based INAA was used. The material is homogeneous for fractions 100 mg, as shown by the evaluation of the heterogeneity of the subsampling operation in the 20 locations and by the results of a one-way analysis of variance for the data obtained. The composition of Evernia prunastri varies neither with the region where it grows nor with the date of collection. This work was accomplished under contract with the IAEA.
Eight inorganic substances recommended by ICTA as temperature standard reference materials for DTA and DSC were studied: KNO3, KClO4, Ag2SO4, K2CrO4, quartz, K2SO4, BaCO3 and SrCO3. The content of pure component in each of these substances was determined by classical chemical analysis. The temperatures and the heats of polymorphic transformations of these substances were measured with a Perkin-Elmer DSC-2 differential scanning calorimeter, and DTA studies were performed on a MOM 1500 D Q-derivatograph. The plot heat of transformation by DSCvs. DTA peak area is advanced as a calibration line for the approximate estimation of quantitative DTA effects. The substances studied will be certified as temperature standard reference materials for use in DTA and DSC.
Fly ash of a waste incineration facility in Berlin, Germany has been found to be a very useful multielement reference material.
It can be used for a large number of matrices to be analyzed. It has served as a reference material particularly for environmental
multielement analyses. Components which have been recognized as environmental pollutants are present in higher concentration
levels than in any other multielement reference material commercially available.