Determination of glucose in reference materials by isotope dilution-mass spectrometry

Conclusion The developed mass spectrometric method for glucose is highly precise and seems to be highly specific. The whole analytical procedure is thoroughly investigated and so far standardized. At present its status is that of a candidate reference method.

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Bestimmung von Glucose in Referenzmaterialien mit Isotopenverdünnung-Massenspektrometrie

     

Microanalysis by Laser Ablation-Inductively Coupled Plasma-Atomic Emission Spectrometry in Comparison to Spark Ablation of Certified and Found Minerals Galena, Sphalerite, and Pyrite

A double-tandem technique of inductively coupled plasma-atomic emission spectrometry (ICP-AES) involving laser ablation for the analysis of compact or briquetted minerals on one hand and spark ablation for the analysis of powders on the other is presented. The technical arrangement, the design of the optimized sample chamber, the evaluation of operating conditions, and the test of liquid-solid calibration are described. Both techniques can be used for the determination of elemental compositions of minerals providing a dynamic range from tens of mass-percent down to milligrams per kilogram. The objective of this study was to compare laser ablation (LA)-ICP-AES and spark-ICP-AES with regard to accuracy, precision, and sample turnaround time for multielement analysis of the certified minerals galena GF1, sphalerite SF1, and pyrite PS1. A systematic error of smaller than 3% in both techniques and a random error of smaller than 9 and 5%, respectively, is pointed out. The optimized methods were applied to samples of galena, sphalerite, and pyrite from four deposits each to find fingerprints by different contents of major, minor, and trace elements, which characterize the deposits.     

Bestimmung von Calciumgehalten im ppm-Bereich in Natriummetall mit Hilfe der R?ntgenfluorescenzanalyse

Zusammenfassung Eine Methode zur Bestimmung von Calcium in Natriummetall wird beschrieben. Das Natriummetall wird mit Methanol, H₂O und H₂SO₄ zu Na₂SO₄ umgesetzt, dieses in einem Platin-Tiegel zu Scheiben geschmolzen und diese direkt mit dem Röntgenfluorescenzgerät gemessen (Cr-Röhre, 55 kV, 36 mA; Analysatorkristall LiF; Ca-K-Linie, 113,01°). Die Nachweisgrenze dieser Methode liegt bei 4 ppm und gestattet daher noch eine sichere Aussage über die bei Na-Metall Reaktorqualität geforderte Spezifikation < 10 ppm Ca.

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Determination of ppm amounts of calcium in sodium metal by X-ray fluorescence analysis

The metal is converted to Na₂SO₄ by treatment with methanol, water and sulphuric acid. The salt is fused in a platinium crucible to form disks which can be directly measured in the X-Ray fluorescence apparatus (Cr tube, 55 kV, 36 mA; analyzing crystal LiF; Ca-K-line, 113.01°). The limit of detection of the method is as low as 4 ppm and thus permits reliable statements with regard to the specification < 10 ppm Ca required for reactor quality sodium metal.