Pyrolytically coated graphite

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. 

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

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... 

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)... 

Leung and Henderson (1982) have not been able to confirm these findings of grossly different curve slopes for different types of serum and standard samples. Bettinelli et al. (1985) made a thorough evaluation of the direct measurement of aluminium in serum using GF-AAS with the stabilized temperature furnace with the L vov platform. Their recommendation was to use pyrolytically coated graphite tubes and to keep the method as simple as possible with minimal sample pre-treatment. Slavin (Personal Communication) also has been unable to observe major slope change problems between aqueous and... 

Calibration is carried either by means of internal standard addition or against a calibration curve from lead-spiked blood. For routine purposes the much simpler and faster method of calibration with lead-spiked blood can be applied. To minimise matrix effects the use of Zeeman GF-AAS and pyrolytically coated graphite tubes with a L vov platform is recommended, but this is instrument-dependent. 

The introduction of pyrolytically coated graphite tubes and the L vov platform technique in GF-AAS as well as of the Zeeman-GF-AAS technique offer improved possibilities to reduce matrix effects when measuring tooth lead in aqueous solutions. Where these techniques are available calibration with lead-spiked tooth solutions can be applied. Otherwise the analyses must be carried out by means of internal standard addition. The accuracy of the analytical procedure should be assessed by interlaboratory comparison, since, at present, no reference material of human teeth is available. 

Urine (Matusiewicz and Barnes, 1985) - NIOSH-NBS freeze dried urine is reconstituted in water. 50 nL samples are determined. Instrumentation Plasma-Therm model 5000D ICP-AES spectrometer. Instrumentation Laboratory FASTAC II pneumatic nebulizer/aerosol delivery system to deliver sample to a model IL655 furnace for graphite furnace vaporization at 2500°C. Argon plasma, 40.68 MHz, A = 231.60 nm, pyrolytically coated graphite tube with platform. Detection limit 0.9 hqIL (45 pg Ni) by peak area, 12 /peak height. Urine reference material found 1.05 mg/L (RSD 2.1%), expected 1.01 0.11 mg/L. 

Figure 72 Heating characteristics of (A) the inner wall of a pyrolytically coated graphite tube, (B) a L vov platform, and (C) the inner surface of a solid sampling cup. (Adapted from U. Vdllkopf, Z. Grobenski, R. Tamm, and B. Welz, Analyst (London), 1985, 110, 573)...

Another ETV system is a modified version of an AAS atomization chamber. The sample is placed on a pyrolytically coated graphite microboat supported by a carbon rod and its mounting assembly. The vaporization heating cycle is controlled by a programmable power supply. The vaporizer assembly is connected to the plasma by a PTFE tube (12 cm in length). 

Pyrolytically coated graphite tubes Transversely heated tubes... 

Atomic absoiption spectrometer with background correction Graphite furnace with autosampler and pyrolytically coated graphite tubes Monoelement aluminum hollow cathode lamp Aluminum standard, 1 g/Iiter (Al metal in 0.3 M HCl)... 

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