Pressure digestion, trace analysis

As to the analysis of trace elements in paper, cardboard and raw materials for the production of paper, high concentration elements such as Cu, Fe or Ti can easily be determined by FAAS Cd and Pb are frequently analysed by GFAAS. Cadmium in pulp and paper was determined by AAS after pressurised digestion with nitric acid [145]. An interlaboratory comparison of Cd in wrapping paper was reported, mainly based on pressure digestion in FIFE bombs with sub-boiled nitric acid, followed by ETAAS [59]. For wrapping paper used for foodstuffs, next to the total content of toxic heavy metals, the soluble or leachable fraction is of particular interest. 

H. Matusiewicz, R.E. Sturgeon, S.S. Berman, Trace element analysis of biological material following pressure digestion with nitric acid-hydrogen peroxide and micro-wave heating, J. Anal. At. Spectrom. 4 (1989) 323-327. 

The loaded filters were digested with nitric acid under pressure at 160 °C. The quantitative determination of the concentrations of 23 trace elements (As, Ba, Ca, Cd, Cr, Cu, Fe, K, Mn, Mo, Ni, Pb, Rb, S, Sb, Se, Sn, Sr, Ti, V, Y, Zn, and Zr) was performed by total-reflection X-ray fluorescence analysis (TXRF) after addition of an internal Co standard [STOSSEL, 1987 MICHAELIS, 1988]. Further details of the sampling method and the trace analysis were given in [MICHAELIS and PRANGE, 1988]. 

Matusiewicz, H., Suszka, A., Ciszewski, A. Efficiency of wet oxidation with pressurized sample digestion for trace analysis of human hair material. Acta Chim. Hung. 128, 849-859 (1991)... 

Matusiewicz H, Sturgeon RE and Berman SS (1989) Trace element analysis ofbiolog.cal material following pressure digestion with nitric acid-hydro-gen peroxide and microwave heating. J Anal Atom Spectrom 4 323-327. 

Adrian, W.J. (1973). A comparison of wet pressure digestion method with other commonly used wet and dry ashing methods. Analyst. 98, 213-216 Alcock, N.W. (1987). A hydrogen peroxide digestion system for tissue trace metal analysis, Biol.Trace Bern. Res. 13, 363-370... 

Raw foods were freeze-dried and analyzed for carbon isotopes using mass spectrometry. Cooked foods were prepared following historic recipes, then were freeze-dried prior to analysis. For the trace element analysis, foods (both raw and cooked) were wet ashed using nitric acid in Teflon lined pressure vessels and digested in a CEM Microwave oven. Analysis of Sr, Zn, Fe, Ca and Mg was performed using Atomic Absorption Spectrometry in the Department of Geology, University of Calgary. 

The introduction of inductively coupled plasma (ICP) in inorganic mass spectrometry means that there is an effective ion source operating at atmospheric pressure. Whereas solid mass spectrometric techniques allow direct analysis of solid samples in ICP-MS, the determination of trace impurities or isotope ratios in solid samples is often carried out after digestion and dissolution of the material. For the determination of trace impurities and isotope ratios in liquids, an additional nebulization... 

Digestion of samples using high pressure oxygen bomb combustion is an excellent technique for sample preparation, particularly trace metal analysis. This technique can be applied to most plastics provided that small sample ( 0.25 g) of fine grain sizes of plastics are used. The solutions obtained are clean and easily analysed for metal content against standards prepared in the same solution added to bomb. 

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