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PubMed2003

Determination of cobalt and nickel by graphite-furnace atomic absorption spectrometry after coprecipitation with scandium hydroxide.

Trace amounts of cobalt and nickel in a water sample were quantitatively coprecipitated with scandium hydroxide at pH 8.0-10.5. Because the coprecipitant could be easily dissolved with 1 mol dm(-3) nitric acid, and the presence of up to 10 mg cm(-1) of scandium did not interfere with the graphite-furnace atomic absorption spectrometric determination of cobalt and nickel, the volume of the final solution prepared for the determination could be minimized down to 0.5 cm3. The concentration factor was 400-fold and the detection limits (signal to noise = 2) were 5.0 pg cm(-3) of cobalt and 10.0 pg cm(-3) of nickel in 200 cm3 of the initial sample solution. The 27 diverse ions investigated did not interfere with the determination in at least a 500-fold mass ratio to cobalt or nickel. The proposed method was successfully applied to the determination of trace amounts of cobalt and nickel in river-water samples.

Calibration↗
PubMed2003

Determination of indium by graphite furnace atomic absorption spectrometry after coprecipitation with chitosan.

A sensitive and simple method for the determination of trace amounts of indium in water samples by graphite furnace atomic absorption spectrometry (GFAAS) after coprecipitation with chitosan was investigated. Indium was quantitatively preconcentrated from water samples by coprecipitation with chitosan at pH 7.0-9.0. The coprecipitant was easily dissolved with acetic acid, and indium in the resulting solution was determined by GFAAS. The addition of lanthanum as a chemical modifier was more effective for the atomic absorbance of indium. The detection limit (S/N > or = 3) for indium was 0.04 microg dm(-3), and the relative standard deviations (n = 5) were 3.5-4.5% at 1.0 microg/100 cm3. The results obtained in this study indicate that the proposed method can be successfully applied to the determination of trace indium in water samples.

Journal Article↗
PubMed2004

Simultaneous direct determination of aluminum, calcium and iron in silicon carbide and silicon nitride powders by slurry-sampling graphite furnace AAS.

A fast and accurate analytical method was established for the simultaneous direct determination of aluminum, calcium and iron in silicon carbide and silicon nitride powders by graphite furnace atomic absorption spectrometry using a slurry sampling technique and a Hitachi Model Z-9000 atomic absorption spectrometer. The slurry samples were prepared by the ultrasonication of silicon carbide or silicon nitride powders with 0.1 M nitric acid. Calibration curves were prepared by using a mixed standard solution containing aluminum, calcium, iron and 0.1 M nitric acid. The analytical results of the proposed method for aluminum, calcium and iron in silicon carbide and silicon nitride reference materials were in good agreement with the reference values. The detection limits for aluminum, calcium and iron were 0.6 microg/g, 0.15 microg/g and 2.5 microg/g, respectively, in solid samples, when 200 mg of powdered samples were suspended in 20 ml of 0.1 M nitric acid and a 10 microl portion of the slurry sample was then measured. The relative standard deviation of the determination of aluminum, calcium and iron was 5 - 33%.

Journal Article↗
PubMed2004

The interference effect of a mixture of magnesium, aluminium, sulfate and chloride on the atomization and vaporization of manganese in graphite furnace atomic absorption spectrometry.

In this study, the interference effects of Al3+, Mg2+, Cl- and SO4(2-) ions on the determination of manganese by graphite furnace atomic absorption spectrometry (GFAAS) were investigated. At first, the interferences caused by Al2(SO4)3, AlCl3, MgCl2 and MgSO4, which are the most possible major compounds for the combinations of the ions mixed, were individually considered. Then, the effects caused by mixtures containing various amounts of MgSO4 and AlCl3 were studied. If the pyrolysis temperature is below 800 degrees C, AlCl3 changes the vaporization mechanism of manganese. These interferences disappear at higher pyrolysis temperatures. At the same time, aluminum salts may cause the formation of refractory compounds between aluminum and manganese (like spinel MnAl2O4) that shift the absorption signals of manganese to higher temperatures. Magnesium sulfate, by itself, does not cause any depression of manganese signals. In fact, it acts as a modifier, preventing volatilization losses of manganese during the pyrolysis step. A conclusion was reached that detailed investigation of the interferences in a complex media is a very difficult experimental and theoretical task. To solve practical problems, one may better follow the general notions developed in GFAAS toward complex matrices.

Journal Article↗
PubMed2004

Determination of vanadium in heavy oils by atomic absorption spectrometry using a graphite furnace coated with tungsten.

A simple and rapid method was established for the direct determination of vanadium in an oil sample using the tungsten-coated graphite-furnace AAS. The interference of the sulfur compound could be suppressed by choosing the ashing temperature. If the sulfur concentration in the sample is diluted to 1.0 wt% or less, the interference can be suppressed. This proposed method should make important contributions to the quality control of petroleum refineries.

Journal Article↗
PubMed2005

Optimization of a chemical modifier in the determination of selenium by graphite furnace atomic absorption spectrometry and its application to wheat and wheat flour analysis.

A method for the determination of total selenium in wheat and wheat flour using graphite furnace atomic absorption spectrometry (GFAAS) with palladium/ascorbic acid as a chemical modifier was studied. The effects of nickel nitrate, palladium/ascorbic acid, and palladium/magnesium nitrate as chemical modifiers on the sensitivity in the determination of selenite, selenate and selenomethionine by GFAAS were compared. The palladium/ascorbic acid modifier was used for the determination of total selenium in wheat and wheat flour, because the oxidation states of the selenium ion are not important in the determination. The detection limit was estimated to be 1 microg L(-1) (calculated as 3sigma of the blank); the calibration curve was linear for the concentration range 5 - 50 microg L(-1) and the recovery range was 96.66 - 101.80%. The optimal ashing and atomizing temperatures were 1300 degrees C and 2250 degrees C, respectively. The proposed method was successfully applied to the determination of total selenium in wheat and wheat flour.

Ascorbic Acid↗
PubMed2005

Determination of chromium, copper and lead in river water by graphite-furnace atomic absorption spectrometry after coprecipitation with terbium hydroxide.

Coprecipitation with terbium hydroxide quantitatively recovered trace amounts of chromium(III), copper(II) and lead(II) at pH 8.4 - 10.8, 8.0 - 11.5 and 8.7 - 11.5, respectively. The precipitate was dissolved in 0.85 mol dm(-3) nitric acid, and the analytes were determined by graphite-furnace atomic absorption spectrometry (GF-AAS). The presence of terbium (up to 7 g dm(-3)) did not interfere with the determination. The detection limits were 0.3 microg dm(-3) for chromium, 0.4 microg dm(-3) for copper and 0.5 microg dm(-3) for lead, when the analytes in 200 cm3 of the sample solution were concentrated into 10 cm3. The ions added to river or seawater were quantitatively recovered. Chromium and copper in a contaminated river water were successfully determined.

Journal Article↗
PubMed2005

Determination of cadmium in spring water by graphite-furnace atomic absorption spectrometry after coprecipitation with ytterbium hydroxide.

A coprecipitation method with ytterbium hydroxide was studied for the determination of cadmium in water samples by graphite-furnace atomic absorption spectrometry. Up to 40 ng of cadmium in water samples was quantitatively coprecipitated with ytterbium hydroxide at pH 8.0-11.2. The concentration factor was 100 fold. The coprecipitated cadmium was sensitively determined without any influence of ytterbium and the calibration curve was linear from 0.1 to 4 ng/mL of cadmium. The detection limit (signal/noise = 2) was 2.9 pg/mL in 100 mL of the initial sample solution. Twenty-nine diverse ions tested did not interfere with the determination in at least a 10000-fold mass ratio to cadmium. The proposed method was successfully applied to the determination of cadmium in spring water.

Cadmium↗
PubMedDate not supplied

Graphite furnace atomic absorption spectrometric determination of lead and cadmium extracted from ceramic foodware: Collaborative Study.

A modification of the official flame atomic absorption spectrometric (FAAS) method for determining lead and cadmium extracted from ceramic foodware was collaboratively studied. In the modified method, graphite furnace atomic absorption spectrometry (GFAAS) is substituted for FAAS. The modified method also includes mandatory quality control procedures to improve method performance. The extraction procedure of the official method (leaching with 4% acetic acid for 24 h at room temperature) remains unchanged. Seven laboratories analyzed blind duplicate portions of 3 ceramicware leach solutions containing Pb at concentrations of 0.0196, 0.403, and 3.73 microg/mL and Cd at concentrations of 0.00236, 0.0456, and 0.544 microg/mL. Performance of the modified method compared well with that of the official method. The repeatability relative standard deviation (RSDr) ranged from 0.87 to 6.7% for Pb and from 3.7 to 11% for Cd. The reproducibility relative standard deviation (RSDR) ranged from 4.5 to 12% for Pb and from 7.0 to 11% for Cd. Accuracy of collaborator results was 97-98% for Pb and 93-101% for Cd. Quality control results and quantitation limits were excellent. Method quantitation limits varied among laboratories from 0.005 to 0.019 microg/mL for Pb and from 0.0004 to 0.0019 microg/mL for Cd. The modified method was adopted First Action by AOAC INTERNATIONAL.

Cadmium↗
PubMedDate not supplied

Collection and preparation of sidestream cigarette smoke for trace elemental determinations by graphite furnace atomic absorption spectrometry and inductively coupled plasma mass spectrometry.

A novel method for the collection and preparation of sidestream cigarette smoke condensate is described for trace elemental analysis by inductively coupled plasma mass spectrometry and graphite furnace atomic absorption spectrometry. The smoke collection method utilizes a specially designed chimney that collects and directs the sidestream smoke (SS) to a 2-stage trapping system consisting of an impaction trap followed by a 0.8 microm mixed cellulose ester filter. The samples are digested with nitric acid in a commercial heating block before analysis. The method limits of detection (LODs) are 1, 0.2, 2, 9, 6, and 7 ng/cigt for As, Cd, Pb, Ni, Se, and Cr, respectively. The SS collected from an industry reference cigarette, 1R4F, produced by the University of Kentucky was analyzed. The concentrations of As, Cd, and Pb in 1R4F were determined to be 27.3+/-2.1, 412+/-14, and 43.8+/-2.0 ng/cigt, respectively, while the concentrations of Ni, Cr, and Se are below the method LOD. Consequently, this novel method successfully addresses contamination, instrumentation, and collection issues for performing trace elemental analysis of sidestream cigarette smoke condensate.

Mass Spectrometry↗
PubMedDate not supplied

Study of the versatility of a graphite furnace atomic absorption spectrometric method for the determination of cadmium in the environmental field.

Cadmium is a representative example of trace elements that are insidious and widespread health hazards. In contemporary environmental analysis, there is a clear trend toward its determination over a wide range of concentrations in complex matrixes. This paper describes a versatile method for the determination of Cd at various levels (0.1-500 microg/g) in several sample types, such as soils, sediments, coals, ashes, sewage sludges, animal tissues, and plants, by graphite furnace atomic absorption spectrometry with Zeeman background correction. The effect of the individual presence of about 50 elements, with an interference/analyte concentration ratio of up to 10(5), was tested; recoveries of Cd ranged from 93 to 106%. The influence of different media, such as HNO3, HCI, HF, H2SO4, HClO4, acetic acid, hydroxylammonium chloride, and ammonium acetate, in several concentrations, was also tested. From these studies it can be concluded that the analytical procedure is scarcely matrix dependent, and the results obtained for a wide diversity of reference materials are in good agreement with the certified values.

Cadmium↗
PubMedDate not supplied

Electrothermal atomization of arsenic, antimony and thallium using a graphite atomizer with refractory metal platforms.

The electrothermal atomization of the volatile elements arsenic, antimony and thallium from a refractory metal platform consisting of a tungsten coil and/or a refractory metal foil with the dimensions of a conventional graphite platform was studied. Several combinations of refractory metal platforms were investigated, as follows: W platform; Ta platform; W coil; W coil on a W platform and W coil on a Ta platform. The best combination for these elements as regards both thermal stabilization and sensitivity is the W coil on a Ta platform. Thermal stabilization is also achieved with a W coil on a W platform. The presence of Pd-containing chemical modifier favors the thermal stabilization of the analytes. The sufficient amount is 2 micrograms of Pd. The maximal temperatures of pyrolysis are higher (arsenic, antimony) or equal (thallium) to those when using different chemical modifiers, added as solutions. It may be concluded, that the refractory metal platforms act as "built-in modifiers". They are suitable for the determination of arsenic, antimony and thallium in samples of complex matrix composition where high thermal stability of the analytes during the pyrolysis step is required.

Air Pollutants↗
PubMed2001

[Study on determination of trace cadmium in Chinese medicine loulu by graphite furnace atomic absorption spectrometry].

A method for the determination of trace cadmium in chinese medicine Loulu by graphite furnace atomic absorption spectrometry (GFAAS) has been described. The matrix modifier and its proper concentration, the influence factors including ashing and atomization temperature, atomization time and coexisting ions were investigated. Under the optimum experimental conditions, the detection limit and the relative standard deviation of the method were 0.06 ng.mL-1 and 2.43% (n = 11), respectively. The recovery was between 97% and 105%. The method is simple, rapid and accurate, and can eliminate the matrix effect. It has been applied to the direct determination of trace cadmium in chinese medicine Loulu with satisfactory results.

Cadmium↗
PubMed2001

[Determination of lead and arsenic in copper aspirinate by graphite furnace atomic absorption spectrometry].

A graphite furnace atomic absorption spectrometric method has been established to determine trace lead and arsenic in copper aspirinate, a new anti-inflammatory and anti-thrombotic agent. The sample is pretreated by ashing at 530 degrees C in the presence of Ni (NO3)2, followed by dissolution with HNO3. The method is simple and has a low detection limit. The relative standard deviation is 11%-15%, the recovery is 92%-112% for lead and 86%-119% for arsenic.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2001

[Determination of lead in whole blood by graphite furnace atomic absorption spectrometry with matrix modifier and L'vov platform].

Lead in whole blood has been determined by graphite furnace atomic absorption spectrometry with matrix modifier and L'vov platform. It's found that addition of the mixture solution of 0.6% NH4H2PO4 and 0.4% NH4NO3 as matrix modifier, the ash temperature will increase up to 900 degrees C. 750 degrees C is practically used for ash temperature. D2 lamp is used for background correction. Lead in whole blood was directly determined after addition of 0.3% Triton X-100 without digestion. The analytical results of six whole samples is satisfactory. The recoveries are 93%-106%. The relative standard deviations are 3%-7%. The sensitivity of characteristic mass is 6.0 pg/1%.

Humans↗
PubMed2001

[Determination of arsenium and lead in traditional Chinese medicines by graphite furnace atomic absorption spectrometry].

The samples were processed by pressure dissociation method and by using HNO3-HClO4 as oxidant. The matrix modifiers were PdCl2 for As and (NH4)2HPO4 for Pb. The effects of matrix modifier quantity, ashing temperature, atomization temperature and element interference on the determination of arsenium and lead were investigated. Under the optimum conditions, arsenium and lead in traditional Chinese medicines were determined by graphite furnace atomic absorption spectrometry. The linear range of calibration curve was 0-300 ng.mL-1 and 0-80 ng.mL-1, the detection limit was 3.75 ng.mL-1 and 1.8 ng.mL-1, the sensitivity was 9.3 ng.mL-1 and 2.6 ng.mL-1, the mean recovery was 95.7% and 99.6%, respectively to As and Pb. The method is simple, rapid, sensitive, accuracy and of high practical application value.

Arsenic↗
PubMed2000

[Determination of trace Pb and Cd in water treatment reagent by graphite furnace atomic absorption spectrometry].

The optimum conditions for the determination of trace Pb and Cd in water treatment reagent by graphite furnace atomic absorption spectrometry were studied in detail in this paper. The results show that the long and tedious pretreatment process was cut down by calibrating background with D2 lamp and NH4H2PO4 as matrix modifier. The determination limits were 0.65 microgram.L-1 and 0.12 microgram.L-1 for (Pb and Cd) and linear ranges were 0-50 micrograms.L-1, 0-20 micrograms.L-1 for Pb and Cd, respectively. Rate of recovery was 90%-110%. This method is accurate, quick and simple, and can be used successfully to determine actual samples.

Cadmium↗