Construction and performance of an a.c. modulated magnet for Zeeman atomic absorption spectroscopy

A Zeeman atomic absorption spectroscopy system has been constructed utilizing a 50 Hz sine wave modulated magnetic field that can be directed either parallel or perpendicular to the optical axis. The amplitude of the magnetic field strength is adjustable up to 10 kG at a maximum power consumption of 0.7 kW.The readout system allows normal atomic absorption as well as d.c. and a.c. Zeeman atomic absorption measurements. Plots of experimental sensitivity vs magnetic field strength and analytical curves are in agreement with theoretical predictions.Experiments in the presence of filter simulated and real background absorbance show that the described Zeeman instrument is capable of correcting background absorption up to two absorbance units.     

The160Tb →160Dy decay

Gamma-ray spectra in the decay of¹⁶⁰Tb were measured with the aid of two coaxial Ge(Li) spectrometers. Absolute intensities and multipolarities were obtained. Three new transitions of 486·5 keV, 1069 keV, and 1102·5 keV were found and introduced into the decay scheme. The level scheme is discussed from the point of view of the generalized model of the nucleus. Experimental data show the 1264·4 keV level to be a two-quasi-particle state of the p p (411–523) type. The beta-transition from the ground state of¹⁶⁰Tb (p 411+n 521) to this two-quasi-particle state with logft=8·00 ± 0·05 is interpreted as -forbidden.The authors are indebted to Prof. K. E. Alexandrov, K. A. Gromov, and E. P. Grigoriev for useful remarks and interest concerning the work.     

The structure of the excited states in84Rb

Conclusion On the basis of the simple shell-model the anomalously high admixture of the E4-radiation to the M3-transition deexciting the isomeric state^84mRb has been explained. The exact evaluation of the amount of this admixture would require, however, detailed theoretical calculations considerating the configuration mixing in the wave functions of the 3⁺ and 6⁺ states in⁸⁴Rb.     

Influence of the temporal response of the detection system upon atomic absorption analytical curves for steady state and transient absorption cells and

The general expression for the atomic absorption signal is modified to allow for a possible time-dependence of the source emission line profile and the     

Data treatment in multi-wavelength detection in HPLC of biochemical compounds

Summary The paper discusses the various methods for the processing of data obtained for the separation of proteins with HPLC equipped with a multi-wavelength detector. Specific difficulties are encountered because of the complexity of protein mixtures and the high similarity of protein spectra. Depending on the type of the requested information, proper data treatment methods should be selected. These are: ratio recording, multi-component analysis and curve resolution.

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Datenverarbeitung für die Multi-Wellenlängen-Detektion bei der HPLC von biochemischen Verbindungen

Zusammenfassung Die verschiedenen Methoden werden diskutiert zur Verarbeitung der bei der HPLC-Trennung von Proteinen mit Hilfe eines Multi-Wellenlängen-Detektors erhaltenen Daten. Spezifische Schwierigkeiten treten dabei auf wegen der Komplexität von Proteingemischen und der großen Ähnlichkeit der Spektren. Je nach Art der gewünschten Information sollten die geeigneten Datenverarbeitungsverfahren ausgewählt werden: Verhältnis-Registrierung, Mehrkomponenten-Analyse und Kurvenauflösung.

     

On Sensitivity and Detection Limit with Reference to Flame Spectrometry

Apparently and amazingly, the concepts of sensitivity and detection limit are still a matter of debate among flame spectroscopists. Probably the papers on this issue by Willis¹ and West² and certainly some misleading statements would have been left unwritten, if these authors had taken the elementary precaution of consulting the pertinent literature^3-7 or an appropriate textbook⁸. Surely there is no need to resort to “normal English usage”² when discussing well-defined scientific concepts. No doubt, most of the confusion stems from the fact that the pioneering articles have been written in German and from the lack of a consistent English, terminology. One frightening example is offered by Ramirez-Muñoz⁹ who introduces no less than sixteen different terms, freely interchanging sensitivity and detection limit. But perhaps, it is not too late to restore the damage.     

Comparison of line and continuous sources in atomic absorption spectrophotometry

Expressions are given for the absorption signal (absorbance or fraction absorbed) in atomic absorption spectrophotometry with a line source and a continuous source, respectively. A theoretical and experimental comparison is made between the shape of the working curves, the magnitude of the signals, and the limits of detection in both cases. The significance of the spectral bandwidth of the monochromator and the absorption line profile is discussed. With a good medium-dispersion monochromator, a continuous source offers several distinct advantages and yields detection limits which are approximately the same as those obtained with a hollow-cathode discharge tube.     

Determination of barium and strontium peroxides (active oxygen) in igniters in small-arms tracer ammunition

A method is proposed for the determination of barium and strontium peroxides (active oxygen) in igniters in small-arms tracer ammunition. The sample is treated with dilute hydrochloric acid (1 + 9) which dissolves the magnesium powder almost instantaneously and then dissolves the barium or strontium peroxides within 10-30 min. The solution is then filtered to remove the organic substances (calcium resinate, "Parlon". Toluidine Red toner, and zinc stearate) and the peroxide is determined by means of the colour of the titanium-peroxide complex. It is shown that igniter mixes and igniters used in small-arms tracer ammunition deteriorate on storage.