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- Messtechnische Rückführung (2)
- Permeable reactive barriers (2)
- Qualitätsmanagement (2)
- Radioindicator (2)
- Uranium (2)
- Akkreditierung (1)
- Audits (1)
- Carrier gas hot extraction (1)
- Eignungsprüfungen (1)
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Veränderungen als "kontinuierliche Verbesserungen"? - Akkreditierungsanforderungen an Laboratorien
(2015)
Zurzeit sind einige für Laboratorien wichtige internationale Normen in Überarbeitung, darunter DIN EN ISO/IEC 17025 als die wohl wichtigste. Das wird für die Laboratorien Veränderungen mit sich bringen. Aber auch unabhängig von Normenrevisionen ändern/verschärfen die Akkreditierungsstellen ihre Anforderungen, worauf die akkreditierten Laboratorien sich einstellen müssen.
Ein Qualitätsmanagement (QMS) nach DIN EN ISO/IEC 17025 [1] für ein analytisches Labor muss technische Anforderungen (s. [2]) und Managementanforderungen umsetzen. Letztere werden hier kurz vorgestellt. Als Kompetenzbestätigung durch eine unabhängige Stelle kommt heute der Akkreditierung des Labors, für die das QMS eine Voraussetzung ist, eine wesentliche Bedeutung zu.
Ein Qualitätsmanagementsystem (QMS) nach DIN EN ISO/IEC 17025 [1] einzuführen und zu betreiben, ist für analytische Laboratorien in Deutschland heutzutage praktisch ein Muss. Es ist Voraussetzung für die Akkreditierung, und es kann eine Kunden- oder Behördenforderung sein. Von den vielfältigen Fragestellungen, die ein QMS eines Laboratoriums ausmachen, werden hier die technischen Aspekte angesprochen.
This study was undertaken to investigate the long-term performance of hydroxyapatite (HAP) as reactive material for the removal of uranium in passive groundwater remediation systems. 237U used as a radioindicator enabled tracking the movement of the contamination front through a test column without taking samples or dismantling the apparatus. The stoichiometric ratio between uranium and HAP was found to be 1:(487±19). Uranium removal by HAP is of pseudo first-order kinetics and the rate constant was measured to be (1.1±0.1)×10-3 s-1. HAP can sorb more than 2900 mg/kg uranium. Possible reaction pathways of uranium and HAP are discussed. The data obtained enable the calculation of ideal lifetime for permeable reactive barriers (PRB) using HAP for uranium removal neglecting hydrological factors that may impair the function of PRBs.
This study was undertaken to investigate the long-term performance of elemental iron as reactive material for the removal of uranium in passive groundwater remediation systems. By using 237U as a radioindicator it was possible to track the movement of the contamination front through a test column without taking samples or dismantling the apparatus. The stoichiometric ratio between uranium and iron was found to be 1:(1390±62). The reaction between iron and uranium is of pseudo first-order kinetics and the rate constant was measured to be (1.1±0.09)×10-3 s-1. These data enable the calculation of ideal lifetime for permeable reactive barriers (PRB) using iron for uranium removal neglecting hydrological factors that may impair the function of PRBs.
The special importance of the analysis of non-metals in high purity metals, which will serve as national standards for elemental analysis in Germany, is illustrated for oxygen and nitrogen. The typical range of the mass fraction of oxygen and nitrogen in these materials is below 10.MU.g/g, often close to 1.MU.g/g. The two methods applied at BAM for these measurements are classical carrier gas hot extraction (HE) and carrier gas hot extraction after activation with photons (PAA-HE). The approach, the methods and their advantages and limitations are discussed. Comparative results from the measurement of oxygen and nitrogen in Cu, Fe, Ga, Pb, Sn and W are presented. (author abst.)
Zusammenfassung
The working principle of nuclear analytical methods (NAMs) is not influenced by the chemical bond. Consequently, they are independent counterparts to the well-known chemical procedures. NAMs obey fundamental laws or can be described and understood thoroughly. This qualifies them as candidates for reference methods. Although following similar nuclear reaction schemes, they comprise bulk analyzing capability (neutron and photon activation analysis) as well as detection power in surface near regions of solids (ion beam techniques). Prominent features of NAMs are sensitivity, selectivity, multielement determination and linearity of the calibration function covering a concentration range of several orders of magnitude. Moreover, ion beam techniques allow depth profiling with nm-resolution in several cases while the ion microprobe additionally offers a lateral resolution in the wm-scale. As NAMs require expensive apparatus (nuclear reactor, accelerator in radioactive control areas) their availability is restricted to a small number of suitably equipped institutes. However, they are able to solve complex analytical tasks, take part in key comparisons and play an essential role in the certification of reference materials.