Construction of a thermoanalyzer for DTA-TD-TMAG-T measurements on metals up to 1100 °C

A thermoanalyzer is described for the simultaneous testing of metals and alloys by three methods: differential thermal analysis (DTA), thermal dilatometry (TD) and thermomagnetometry (TMAG). One reference specimen is used as a standard for each of the above kinds of analysis. Measurements can be performed in vacuum or in a static or dynamic atmosphere of gases at any pressure between normal and 5× 10^–5 Torr. The temperature of the sample can be changed linearly in the range 20–1100 °C. DTA and TD are performed classically, whereas TMAG is based on the temperature and magnetic field-dependences of the reversible magnetic susceptibility of the sample. Some analysis results are presented.

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Zusammenfassung Es wird ein Thermoanalysator zur simultanen Untersuchung von Metallen und Legierungen durch drei Methoden beschrieben: Differentialthermoanalyse (DTA), Thermodilatometrie (TD) und Thermomagnetometrie (TMAG). Für alle drei Verfahren wurde die gleiche Referenzsubstanz als Standard benutzt. Messungen können im Vakuum oder is statischer bzw. bewegter Atmosphäre von Gasen beliebigen Druckes zwischen Normaldruck und 5·10^–5 Torr durchgeführt werden. Die Temperatur der Probe kann zwischen 20 und 1100 °C linear variiert werden. Während DTA und TG die herkömmlichen Verfahren zu Grunde liegen, basiert TMAG auf der Temperatur- und Magnetfeldabhängigkeit der reversiblen magnetischen Suszeptibilität der Probe. Einige Analysenergebnisse wurden dargestellt.

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: (), () (). . , 5·10^–5 . 20–1100°. , . .

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Presented at the 4th European Symposium on Thermal Analysis and Calorimetry, Jena, GDR, August 1987.     

Ueber die Dissociation wasserhaltiger Salze

Ohne Zusammenfassung     

Zur Bestimmung des specifischen Gewichtes von Gasen

Ohne Zusammenfassung     

Ein Spektralbrennereinsatz

Ohne Zusammenfassung     

Simultaneous quantitative analysis of letrozole, its carbinol metabolite, and carbinol glucuronide in human plasma by LC-MS/MS

Letrozole is an efficient endocrine treatment of postmenopausal breast cancer, however, not all patients benefit from this treatment, and moreover, severe side-effects like arthralgia frequently lead to discontinuation. To better understand inter-individual variability in drug response and side-effects, plasma analysis of steady-state concentrations of letrozole and its major metabolites is crucial. We developed a rapid, sensitive, and specific method for the simultaneous quantification of letrozole and its metabolites 4,4′-(hydroxymethylene)dibenzonitrile (carbinol) and bis(4-cyanophenyl)methyl hexopyranosiduronic acid (carbinol-gluc) by UHPLC-ESI-MS/MS using in-house synthesized, stable isotope-labeled internal standards. Following solid-phase extraction in BondElut C18 96-well plates, the analytes were separated on a ZORBAX Eclipse XDB-C18 column (1.8 μm, 4.6 × 50 mm) with a gradient of acetonitrile in 0.1% acetic acid in water and detected on a triple quadrupole mass spectrometer with electrospray ionization in the multiple reaction monitoring mode. Lower limits of quantification were 20, 0.2, and 2 nM for letrozole, carbinol, and carbinol-gluc, respectively. The assay has been validated according to FDA guidance and applied to the analysis of 20 plasma samples of postmenopausal breast cancer patients treated with 2.5 mg of letrozole per day. Mean plasma levels (±SD) were 366 ± 173, 0.38 ± 0.09, and 34 ± 12 nM for letrozole, carbinol, and carbinol-gluc, respectively. Our rapid and sensitive mass spectrometry based method enables future pharmacokinetic investigations of letrozole outcome.     

Comparison of packed and capillary columns for quantitative gas chromatography of triglycerides in milk fat

Summary Quantitative gas chromatography of triglycerides in conjunction with established triglyceride formulae can be used to determine various milk fat parameters. Since the evaluation of, for example, iodine number or content of non-milk fats (foreign fats) in milk fat requires only the separation of triglycerides by carbon number and since repeatabilities, especially of the highboiling triglycerides, have been less acceptable with capillary columns in the past, packed columns have been used exclusively. There is, however, an increasing demand for the use of capillary instead of packed columns and to that end the present investigation has been carried out. To achieve a suitable resolution, with this particularly exacting high-temperature application, a short 5 m capillary column of extreme temperature stability has been used. As well as modification of various analytical conditions different injection techniques have been investigated. On-column, PTV and split injection were compared with regard to repeatability. The cold-on-column injection technique was found to produce the best results, being comparable to the excellent precision of a packed column. Thus, a method is now available by means of which the determination of milk fat parameters by the triglyceride formulae, such as the amount of foreign fats in milk fat, can now be carried out with a standardized capillary column.