Einige systematische Fehlerquellen bei der Bestimmung von Elementen im ng- und pg-Bereich mit der Atomabsorptionsspektrometrie mit flammenloser Anregung im Graphitofen

Graphite furnace atomic absorption spectrometry with graphite cloth ribbon for selenium determination

“…It has been pointed out that porosity and the gas permeability of the graphite tube cause a source of lowering sensitivity and interference, but these properties can be reduced by the application of a pyrolytic graphite coating to the wall of the tube (1). However, interferences and sensitivity strongly depend on the quality of the pyrolytic graphite coating (22)(23)(24)(25), and the quality varies during the lifetime of the tube (24). The use of PG tubes was recommended for difficult-to-volatilize elements such as molybdenum and vanadium (3); it was pointed out that PG is not always the optimum surface for use, especially in the presence of some ©…”

Graphite-furnace atomic absorption spectrometric determination of lead and cadmium in foods after solvent extraction and stripping

“…Two factors generally considered when choosing a stripping solution are (1) quantitative back extraction of the elements of choice and (2) amenability to precise measurement by the chosen instrumentation. While the first is relatively straightforward and has been achieved for APDC-chelate systems with respect to lead, cadmium, chromium, cobalt, copper, iron, zinc, and nickel (15,18), the latter is often of greater importance with respect to accuracy and precision when the composition of samples varies and when samples must be compared with synthetic standards (14).…”

“…Graphite-furnace analysis of MIBK-APDC extracts has been reported (7,12,13); however, problems were found with pipetting the organic phase (7) and, for cadmium, nickel, and cobalt, the absorption signal varied by as much as 100%, depending on the time difference between injection of the extract into the furnace and the start of the drying cycle (12,13). Volland et al (14) reported that in determination by graphite-furnace atomization of metals in the presence of APDC and MIBK or chloroform, losses occur due to volatility of organometallic compounds.…”

Effect of graphite furnace substrate materials on analyses by furnace atomic absorption spectrometry

“…Many workers have observed differences in analytical sensitivity or the extent of interferences when ordinary and pyrolytic graphite are compared. Volland et al (21) observed differences in the extent of halide interferences on Fe, Ni, Mn, and Mo. Montgomery and Peterson (22) showed that pyrolytically coated graphite tubes deteriorated rapidly when NH4NO3 was used for the determination of Cu in seawater.…”