No abstract

Thirty‐one geochemical reference samples have been analysed for Ag, B, Ge, Mo, Sn, Tl and W by atomic emission spectrographic techniques with air‐jet controlled d.c. arc. The paper presents description of techniques and the data are compared to those from other studies.

Statistical analysis was used to select internal standards in order t o improve the precision and accuracy of multi-element atomic emission spectrometry (AES) under various matrix conditions. The process of sample vaporisation f r o m a carbon arc electrode was investigated. The similarity in behaviour of the analyte elements was found to be reduced at the late vaporisation stages. Model calculations of vapour diffusion and experimental measurements of element accumulation in the electrode body (walls and base) were used to explain this effect. The investigations showed that a possible cause of the reduced effectiveness of an internal standard was sorption in the electrode. A criterion for selecting internal standards, based o n measurement of the average signal delay of curve I(t), was proposed for increasing the efficiency of internal standardisation. It was applied to techniques used for the determination of trace elements in rocks and environmental samples. Keywords : M ulti-elem en t a tom ic emission spec from e tric analysis; in te rna I standard; average signal delay; diffusion into carbon arc electrode Internal standardisation is an often used technique for

Reference samples of soils from the Institute of Applied Physics, Irkutsk (RIAP), the Institute of Geochemistry, Irkutsk (IGI) and the United States Geological Survey, Reston (USGS) were analysed with the aim of determining Ag, B, Ge, Mo, Sn, Tl and W abundances by an atomic emission method with air‐stabilised D.C. arc excitation. Two series of reference samples of soils and bottom sediments, GSS‐1‐8 and GSD‐1‐12 (IGGE), were used to ensure the traceability link for the analytical results. Traceability was also demonstrated through the comparison of measured results by AES and ICP‐MS methods. It is shown that the reference samples GSS‐1‐8 and GSD‐1‐12 satisfied the “fitness‐for‐purpose” criterion (uncertainty U of the certified value should be one‐third to one‐tenth the magnitude of routine laboratory data uncertainty S (S/U > 3‐10)) and can be applied for calibrating AES techniques.

displacements of adjacent particles are maximal, we can conclude that in specimen II the thermal motions at high frequencies are more intense than in chemical oxyhydrate.The above observations show that the specimens of electrochemical aluminum oxyhydrate are further from a state of thermodynamic equilibrium than are specimens of chemical oxyhydrate, and have higher internal and surface energies.Hence we can understand the main source of the high chemical (including sorptive) activity of precipitates If, which in a purely chemical sense is a consequence of a change in the degree of activity of both the metal sorption centers and the terminal hydroxyl groups and aquo groups on account of variation of the AI-OH distance and associated changes in the O-H distance.During ash content measurements on coal based on the intensity of Y rays scattered in the coal layer in a forward direction, competing processes occur in the object of control itself, enabling us to compensate for the influence of such disturbing factors as variations Institute of Beneficiation of Solid Mineral Fuels, Lyubertsy.