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- 2014 (2) (entfernen)
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- CCQM (1)
- Cu-Au alloy (1)
- EDX (1)
- EPMA (1)
- Interlaboratory comparison (1)
- K-values (1)
- WDX (1)
An inter-laboratory comparison organized as a pilot study (PS) has been performed under the umbrella of the Consultative Committee for Amount of Substance – Metrology in Chemistry (CCQM) / Surface Analysis Working Group (SAWG) with the objective to compare k-values measured with Electron Probe X-ray Microanalysis (EPMA) for copper-gold alloys. The k-value, defined as the ratio of the Xray photon intensity of an X-ray characteristic line of the unknown sample to the corresponding one in the reference material, is a rough estimate of the mass fraction of the respective element. Basically, the mass fractions can be calculated from the k-values after applying a matrix correction procedure, which includes empirical approaches, so that traceability gets lost. Due to its physical, measurable nature, the k-value has been selected in the present PS as the primary measurand. The mass fraction has been set as the secondary (derived) measurand. Both EDX and WDX have been employed. The WDX results and the overall comparability between the k-values obtained by EDX and WDX are still in progress.
Hackfleisch erwies sich als eine gute Matrix für mikrobiologische Ringversuche und Interlabor-Vergleichsuntersuchungen, da die aerobe mesophile Koloniezahl sowie der Gehalt an experimentell inokulierten Escherichia coli über den Beobachtungszeitraum von neun Wochen stabil blieb. Das Einfrieren führte allerdings zu einer geringfügigen Verminderung des E. coli-Gehalts, wenn die Proben vor der Analyse bei 5 °C aufgetaut wurden. Somit sollte das Einfrieren von Proben, die auf die Einhaltung mikrobiologischer Kriterien geprüft werden sollen, auch bei Hackfleisch vermieden werden.