High-temperature Ashing Research Articles

Multitechnique multielemental analysis of coal and fly ash

The coal sample is first ashed with high temperature ashing or with RF plasma low temperature ashing. The coal ash or fly ash can be analyzed for major ash elements by fusing with lithium tetraborate in an automatic fusion device, the Claisse Fluxer. The ash samples are also dissolved in a Parr bomb in a mixture of aqua regia and HF. Subsequently, the solutions are analyzed for eight major (Al, Ca, Fe, K, Mg, Na, Si, and Ti) and 20 trace elements (As, B, Ba, Be, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, P, Pb, Sb, Se, Sr, U, V, and Zn) by inductively coupled plasma emission spectroscopy. Mercury in coal and fly ash is determined on a separate aliquot by the cold vapor atomic absorption technique. Fluorine and chlorine in the samples are determined by fusing with Na/sub 2/CO/sub 3/ and Eschka mixture, respectively, and then measuring the two ions in solution with specific ion electrodes. Oxygen in the samples can be determined rapidly and nondestructively by 14-MeV neutron activation analysis. These methods have been tested by analyzing several NBS coal and fly ash standards with good accuracy and reproducibility. 10 tables.

The application of x-ray analysis in the transmission electron analytical microscope (T.E.A.M.) to the quantitative bulk analysis of biological microsamples.

This paper describes: (a)methods for the high and low temperature ashing of biological tissue samples about 10(-4)-10(-5) g in weight; (b)a method of spraying the solubilized ash on to specimen grids which produces droplets of a size convenient for their quantitative analysis in a transmission electron analytical microscope (T.E.A.M.), but without the need to know the actual volume of individual droplets; (c)the construction of standard curves for determining the absolute concentration of Na, Mg, P, S, K, and Ca simultaneously in a given sample. For most of the elements the error in analysis was about 5% or less. It was proposed that the technique is useful for detecting local element-compartments in complex tissues, and thus may be an important aid in the interpretation of the results of point analyses performed on sections taken from adjacent micro-volumes.

高周波酸素プラズマによる低温灰化の生薬学的研究への応用 : センナ葉およびツバキの葉の灰化組織中のシュウ酸カルシウムの観察

Plant tissues are completely ashed at ordinary temperature by very reactive oxygen stream excited in a high-frequency electromagnetic field under a low pressure, preserving mineral microstructures precisely identical with the original tissue matrices. Microscopic examinations of the mineral structures of the ashed tissues readily suggested their valuable contribution to plant taxonomical and morphological studies, as well as in identification of original plants for crude drugs. Systematic studies on mineral microstructures of medicinal plants were taken up and, as the first step, leaves of Cassia angustifolia VAHL and Camelia japonica L., both involving calcium oxalate crystals, were examined through surface and cross-sectional views of the ashed tissues. The results thereby obtained are summarized as follows, in comparison with the conventional Molisch's high temperature ashing method. 1) The low-temperature ashing preserves the mineral microstructures better than the high temperature ashing method and crystals in the ashed tissues retain their original location and shape. 2) Calcium oxalate crystals forming both clustered and solitary bodies are non-reactive with the oxygen plasma so that their geometric constitutions and optical properties of the crystals can be studied well in the ashed tissues, while with the high-temperature ashing the calcium oxalate crystals are considerably destroyed by thermal decomposition during ignition. 3) Cell membrane, nuclei, chloroplasts, leucoplasts, and some other small grains are ashed as they were in the original tissues, suggesting that certain mineral constituents were present in these materials.

A simple diffusion method for the determination of fluoride

A method is described for the determination of sub-microgram amounts of inorganic fluoride. Diffusion on to a thin layer of solid alkali is used to separate fluoride from any contaminants. The diffused fluoride may be determined with an ion-selective fluoride electrode or by spectrophotometric methods.Phosphate and sulphate do not interfere. The interference of halides, carbonate, nitrate and acetate is discussed. Organic material was found not to interfere with the recovery of fluoride except in determinations involving human serum. High-temperature ashing of organic samples was found to lead to loss of fluoride.When used with the ion-selective electrode the method is applicable over the range 0·05 to 200 µg of fluoride.