Pyrolytically coated

Montgomery and Peterson [675] showed that ammonium nitrate used as a matrix modifier in seawater analysis to eliminate the interference of sodium chloride degrades the pyrolytic coating on graphite-furnace tubes. The initially enhanced sensitivities for copper, manganese, and iron are maintained for up to 15 atomisations. There is then a rapid decline to a constant lower sensitivity. The characteristics depend strongly on the particular lot of furnace tubes. To... 

Materials. Gelman 37 mm, type A/E glass fiber, GN-4 0.8 metricel, and DM-800 0.8 membrane filters were used in this study. Spectral quality, pyrolytic coated, graphite furnaces and rods were used in the study. The furnace capacity was 5 yL of solution. Manual sample injections were made with a 5 yL Eppen-dorf pipet 4700 using disposable tips. 

The retention of fission product iodine and xenon by unirradiated and irradiated pyrolytic-carbon-coated (Th,U)C2 fuel particles has been studied in annealing experiments and has been compared with similar studies of the release (or retention) of barium and strontium. The objective was to study the effects of irradiation on the retention of the two types of fission products and to determine the mechanism of release which could account for the observed behaviors. In both unirradiated and irradiated particles, iodine and xenon were found to be retained highly by the impervious isotropic pyrolytic coating which was unaffected by the irradiation. In contrast, the fuel kernel which controls the release of the metallic species is damaged severely by the irradiation, resulting in a marked decrease in its ability to retain the metals. 

Ross et al. [6] analysed samples of soil leachates from laboratory columns and of soil pore water from field porous cup lysimeters for aluminium by atomic absorption spectrometry under two sets of instrumental conditions. Method 1 employed uncoated graphite tubes and wall atomisation method 2 employed a graphite furnace with a pyrolytically coated platform and tubes. Aluminium standards were prepared and calibration curves used for the colorimetric quantification of aluminium. Method 1 gave results which compared favourably with method 2 in terms of both sensitivity and interference reduction for samples containing 1-15 uM aluminium. 

For sample analysis, use a suitable graphite furnace atomic absorption spectrophotometer (GFAAS) equipped with an autosampler, pyrolytically coated graphite tubes, solid pyrolytic... 

C) (pyrolytically-coated furnace) (tantalum-foil lined furnace)... 

Sensitivities for Sc, Y and the lanthanides in pyrolytically-coated and tantalum foiled-lined graphite furnaces [193]. 

The increase in sensitivity from the pyrolytically coated tube has been noted by others [86] who cautioned against impregnation of the graphite tube with salts of elements which form stable carbides (Ta, Si, Nb, Zr, W, La). Decreased sensitivities for V have been obtained following such treatment which was attributed to the possible formation of ternary compounds between the impregnating element, vanadium and graphite, e.g. V—Ta—C. 

Some of the physical and chemical constraints on the flame atomization process — which usually precluded application to solid samples — were overcome with the advent of flameless atomization, initially accomplished with the pyrolytic coated graphite tube (or carbon rod-type) furnace atomizer. The graphite tube is a confined furnace chamber where pulsed vaporization and subsequent atomization of the sample is achieved by raising the temperature with a programmed sequence of electrical power. A dense population of ground state atoms is produced as a result for an extended interval in relation to the low atom density and short residence time of the flame. The earliest use of furnace devices in analytical atomic spectroscopy is credited to a simultaneous development by Lvov [15] and Massmann [16] however, the first application of one such device to a... 

Coated spherical Th02- or U02-particles are increasingly utilized in the fuel of gas-cooled high temperature reactors. Their 50 to 1500 pm core of uranium(IV) oxide is manufactured using conventional sintering techniques. This is then pyrolytically coated with many layers of carbon and silicon carbide (see Section 5.7.5.1). 

Barbosa et al. (2001) described a method for the determination of Bi in whole blood and urine using ET AAS. The method used a pyrolytically coated integrated platform tube coated with a tungsten-rhodium mixture, which acted as a permanent chemical modifier, and this improved the furnace tube lifetime by 80%. Urine samples were diluted 1 + 1 (v/v) and blood samples 1+4 (v/v) with 1% HNO3 Triton X-100. Samples (20 p,L) were injected into the modified tube with a 10 xL volume of Rh. Reported LODs were 3 JgL and 8 igL for urine and blood, respectively. 

Plasma, urine PE Zeeman 3030 Pyrolytically coated graphite tubes Ca Gitelman... 

Urine H Zeeman 9000 Pyrolytically coated graphite tubes Ni Kobayashi 1995... 

Serum, breast V Zeeman Spec- Pyrolytically coated graphite tubes La -(- Ca Leung... 

Urine, serum Zeeman 4100 ZL Pyrolytic coated graphite tubes Pd + Mg Van Dyck 1999... 

Serum, urine bone, soft tissues Sr Serum/urine Dilute with TX-IOO/HNO3. Bone wet digest with HNO3 [N/MT WDC] Atomize from wall of pyrolytically coated graphite tubes [ZETAAS] [N/MT-ZETAAS WDC-ZETAAS] D Haese et al. (1996)... 

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