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PubMed1998

[Determination of trace Al in serum of cancer patients by graphite furnace atomic absorption spectrometry using K2Cr2O7 and surfactant as matrix modifier with molybdenate coated tubes].

Different kinds of graphite tubes and of matrix modifiers have been tested for optimization of operation condition for determination of Al in serum by GFAAS. The effects of different interference ions have been eliminated by adding K2Cr2O7 and Triton X-100 as matrix modifier. The method is suitable for determination of serum of cancer patients. The characteristic mass is 21.15pg/0.0044 A x S. The recovery rate is 104.92. The relative standard deviation is less than 8.17%. The result obtained is satisfactory.

Aluminum↗
PubMed1998

[Determination of selenium by platform graphite furnace atomic absorption spectrometry].

The matrix modifier and its amount, the ashing or atomization temperature of selenium and interference experiment are investigated. The experimental result shows that the application of Pd-Ca as mixed matrix modifier not only reduces interference but also enhances ashing temperature and increases sensitivity. The method can be used directly for the determination of selenium in cereal by platform graphite furnace atomic absorption. The characteristic mass is 39 ng,the detection limit is 0.11 microg/g, the relative standard deviation is 4.9-7.7% and the recovery is 92-100%.

Graphite↗
PubMed2005

[Direct determination of trace lead in chestnut by graphite furnace atomic absorption spectrometry with slurry sampling].

A method for the direct determination of trace lead in chestnut by Graphite Furnace Atomic Absorption Spectrometry (GFAAS) with slurry sampling was developed in the present paper. Ammonium ortho-phosphate was used as a matrix modifier. The effects of slurry preparation, particle size of sample, matrix modifier, ashing temperature, atomization temperature, and common coexisting components on the determination of lead were studied. Under the optimized operating conditions, the detection limit, the relative standard deviation (RSD), and the recoveries of standard addition for this method were 0.47 ng x mL(-1), 6.1% (n = 11) and 90%-106%, respectively.

Fagaceae↗
PubMed2005

[Determination of Pb and Al in blood and hair of child using transverse heated graphite furnace atomic absorption spectroscopy].

Pb and Al in blood and hair of child were determined by transverse heated graphite furnace atomic absorption spectrometry with NH4H2PO4 and Mg(NO3)2 as a modifier, which enhanced the temperature of ashing, eliminated the matrix interference and memorial effect. The method is rapid, simple and accurate. The characteristic mass of the method was 2.3 x 10(-11) g and 2.2 x 10(-11) g for Pb and Al respectively. The relative standard deviation of Pb and Al was 3.0% and 11.4%, respectively, and the recovery was 96%-102%.

Aluminum↗
PubMed2005

[Determination of trace cobalt in water samples by graphite furnace atomic absorption spectrometry after cloud point].

In buffer solution of citric acid monohydrate-disodium hydrogen phosphate at pH 5-7.5, cobalt water samples were chelated by 1-(2-pyridylazo)-2-naphthol (PAN) to form Co-PAN. After water-bath at 66 degrees C for two hours, Co-PAN is extracted into Triton X-100 nonionic surfactant phase and separated from bulk water. Extracted cobalt content was measured by graphite furnace atomic absorption spectrometry. The surfactant phase separated was treated with 0.5% HNO3-0.1% Pd(NO3)2 to remove background interference at 1200 degrees C temperature. The pre-concentration of cobalt in water samples permitted the detection of 0.003 microg x L(-1) (10sigma) with the enhancement factor of 100. The recoveries were 90.5%-106%. The proposed method was applied to the determination of cobalt in water samples and satisfactory results were obtained.

Cobalt↗
PubMed1992

Graphite tattoo: report of a case and differential diagnosis.

A case report underlining the necessity of the biopsy procedure for a pigmented lesion of unknown origin. A female patient was referred for evaluation of a pigmented lesion on the facial keratinized gingiva coronal to the free gingival margin above tooth No. 7. An excisional biopsy revealed a graphite tattoo. A discussion and differential diagnosis of pigmented lesions follows.

Adult↗
PubMed2005

[Determination of cadmium, chromium and lead in Lycoris radiata with microwave digestion technique by graphite furnace atomic absorption spectrometry].

A new method using microwave digestion technique was developed for the determination of cadmium, chromium and lead in Lycoris radiata by graphite furnace atomic absorption spectrometry (GFAAS). Digestion solvents were discussed for sample preparation by microwave digestion technique. The optimum condition of determination by GFAAS was studied in the presence of NH4H2PO4 matrix modifier. The detection limits of Cd, Cr and Pb are 0.066 7, 1.22 and 0.810 microg x L(-1), respectively. The method was applied to the determination of Cd, Cr and Pb in Lycoris radiata samples with satisfactory results. The RSD of determination were lower than 3.1%. The recoveries were from 83.8% to 118%.

Cadmium↗
PubMed1991

Graphite furnace atomic absorption spectrometric determination of blood lead with palladium modification.

In this work we present a graphite furnace atomic absorption spectrometric method for blood lead using palladium as a chemical modifier. Whole blood was diluted 10- fold with a 0.1% v/v triton X-100 solution; 10 microL of this solution and 10 microL of the palladium-based modifier (2 mg Pd/L, 2% w/v citric acid and 0.01 M nitric acid) were injected onto the L'vov platform by using the alternate volume mode. The following furnace operating parameters were used: (a) drying steps, 120 degrees C for 10s and 250 degrees C for 30s; (b) pyrolysis steps, 800 degrees C for 45s (with oxygen) and 1100 degrees C for 25s; (c) atomization, 1600 degrees C for 3s; (d) clean out, 2700 degrees C for 4s. Accuracy was tested by using (i) a NIST standard (SRM-909) and the Behring Control Blood for Metal 1 (OSSD 21) with lead concentrations of 23.7 +/- 2.1 micrograms/L (found: 21.2 +/- 0.7 micrograms/L) and 413 +/- 51 micrograms/L (found: 407 +/- 6 micrograms/L), respectively; (ii) recovery studies (ca. 100 +/- 1%), and (iii) a reported method (mean relative error: 5.1%). Approximate standard deviations of 0.3 (within-run) and 0.7 (between-runs) micrograms Pb/L were found in the precision study. The detection limit (3 sigma) and the characteristic mass (for a 10- microL injection volume) were 0.1 micrograms Pb/L and 15 pg/0.0044 A.s, respectively. The proposed method was used to establish the lead levels of patients with renal insufficiency; a mean concentration (+/- SD) of 59 +/- 39 micrograms Pb/L (range: 12- 160 micrograms Pb/L) was found. The method was interference-free, reliable and reproducible.

Graphite↗
PubMed1975

Ultramicro analysis for copper, cadmium, and zinc in human liver tissue by use of atomic absorption spectrophotometry and the heated graphite tube atomizer.

We describe a method of analysis for copper, cadmium, and zinc in a 15-mg (wet weight) sample of human liver by atomic absorption spectrophotometry. The sample is digested with nitric acid (1.0 mol/liter), evaporated, and dilute HNO3 (10 mmol/liter) added. The reconstituted acid mixture is injected into the graphite tube atomizer for analysis of Cu and Cd and aspirated into the air--acetylene flame for measurement of Zn. The absorbance for each metal is suppressed with increasing pH. NaNO3, KNO3, KCl, and NaCl (e.g.) quench the Cd absorbance in acid solutions that contain no protein, but not in the presence of protein. Metal ions added to the predigestion human liver sample at 10 percent and 100 percent of the intrinsic metal concentrations were, respectively, 93 percent and 90 percent accounted for analytically in the case of Cu, 98 percent and 102 percent for Zn, and 101 percent and 93 percent for Cd. Analysis of a National Bureau of Standards' Bovine Liver Standard Reference Material yielded results corresponding to 99 percent (Cu), 112 percent (Zn), and 91 percent (Cd) of the mean expected concentrations of these metals. The between-run coefficient of variation for the bovine liver material was 6 percent for Cu, 9 percent for Zn, and 10 percent for Cd. For 16 histologically normal samples of human liver, the mean values were: Cu, 26; Zn, 293; and Cd, 6.0 nanograms of metal per milligram dry weight, in agreement with values published previously. The method can be easily and reliably applied to small samples of liver obtained by closed-needle biopsy.

Animals↗
PubMed1975

Determination of serum copper by atomic absorption, with use of the graphite cuvette.

We have established and evaluated a flameless graphite cuvette method for copper in serum. This atomic absorption method provides substantial improvement in sensitivity, adequate accuracy, and acceptable precision, and little sample preparation is required before the analysis. Standard addition studies and measurements of National Bureau of Standards materials indicated that the proposed method is accurate, but that sample pH must be kept between 2 and 3 for high accuracy. Cations and anions that frequently are present in protein-containing samples do not interfere significantly. Sample cross contamination in the syringe must be carefully avoided. Finally, when results for more than 100 patients' sera by this method were compared to those obtained by flame atomic absorption for the same samples, no substantial bias or inaccuracies could be attributed to this new micro-scale method for serum copper. Hence, this method is ideally suited for use on pediatric patients.

Copper↗
PubMed1988

Aluminum determination in whole blood, dialysis solution, and tap water samples from Maracaibo dialysis units (Venezuela) by graphite furnace atomic absorption spectrometry.

Patients with chronic renal failure (CRF) on periodical hemodialysis may accumulate aluminum in tissues and show typical disorders such as dialysis encephalopathy, osteodystrophy, and microcytic anemia. Aluminum contamination of the water used to prepare the dialysis solution (dialysate) is one of the metal sources that may affect people under hemodialysis, especially in units in which untreated water is used. Graphite furnace atomic absorption spectrometric methods for aluminum determination in whole blood, dialysis solution, and tap water samples from CRF patients were developed, based upon the use of the same furnace temperature program. Samples were diluted 4-fold with 0.6% triton X-100 (whole blood) or with 0.01 mol/L nitric acid (dialysis solution and tap water) and analyzed by aqueous standard (blood and tap water) or matrix-matching standard (dialysis solution) calibration curves. The characteristic masses were 33.8, 11.3, and 19.5 pg Al/0.0044 A.s for whole blood, dialysate, and tap water, respectively. In the diluted solutions, the detection limits (2 sigma) for the described methods were 0.5 microgram/L Al (whole blood), 0.4 microgram/L Al (dialysate), and 0.4 microgram/L Al (tap water). The methods were applied to samples from several CRF patients under hemodialysis at Maracaibo University hospital. The data revealed extremely high aluminum levels, which corresponded to the symptoms of dialysis encephalopathy and/or osteodystrophy showed by some of them. The proposed methods are reliable and reproducible.

Aluminum↗
PubMed1977

[Determination of antimony from environmental air in the working area using flameless atomic absorption with a graphite furnace].

Particulates of antimony present in area of plants producing a catalyst containing iron an antimony have been determined. The environmental aereosol, filtered through micropore filters, is analyzed in the form of stabilized aqueous suspension by atomic adsorption flameless graphite furnace. The limit of air revealability permitted by the method is 0.2 mcg/m3. With the above mentioned revealability limit it is possible to perform very rapid drawings of environmental air, so that noxiouslity of even very short-time processing can be controlled.

Air Pollutants↗
PubMed1984

Determination of C lambda for a graphite-walled reference ionization chamber.

A method of evaluation of chamber wall dependent components Am, Aeq and alpha of the absorbed dose conversion factor C lambda, for a graphite wall reference ion chamber is described in this paper. The procedure of utilising such a reference chamber for routine absorbed calibration of commercial dosemeters at high photon energies is also described.

Graphite↗
PubMed1980

Identification of graphite in tissue sections.

Graphite can be identified in tissue sections by its birefringence, in spite of its black color, and by its resistance to conventional incineration, but it is removed by exposure to radiofrequency-excited oxygen plasma. Amorphous carbon is removed by conventional or radiofrequency incineration.

Birefringence↗
PubMed1982

Graphite furnace atomic absorption spectrophotometric determination of 4-hydroxy-3-nitrobenzenearsonic acid, other organic arsenicals, and inorganic arsenic in finished animal feed.

4-Hydroxy-3-nitrobenzenearsonic acid (roxarsone) is administered in animal feed as a growth stimulant over a concentration range of 25-50 ppm. The drug is extracted from 5 g feed with 200 mL aqueous 1.0% ammonium carbonate solution and 5 min of mechanical shaking. Undissolved feed particles are allowed to settle and 1.0 mL aliquot of extract is diluted with 9.0 mL 15% methanol solution. This solution is subjected to sample atomization by a graphite furnace and arsenic detection by atomic absorption spectrophotometry (AAS). Roxarsone recovery from nonmedicated commercial feed fortified at 25 ppm was 103.6% with a relative standard deviation (RSD) of 4.0%. Recovery for 50 ppm fortification was 104.5% (RSD 4.3%). Roxarsone assay results by furnace AAS were compared with results by the current AOAC spectrophotometric method and the AOAC total arsenic method. Results by the 3 methods compare well. The procedure was also used to determine other organic arsenicals and inorganic arsenic in laboratory-fortified feed samples; these recoveries were essentially theoretical.

Animal Feed↗
PubMed1995

Sensitive method for analysis of strontium in human and animal plasma by graphite furnace atomic absorption spectrophotometry.

For long-term pharmacokinetic studies in humans as well as in experimental animals, an analysis of strontium (Sr) with a low detection limit and high sensitivity is necessary. The data presented here describe the optimization of the furnace program and sample handling for measuring Sr in plasma by using graphite furnace atomic absorption spectrophotometry. The method was validated and applied to studies on the pharmacokinetics of SrCl2 in humans and rats. Calibration curves were linear up to 57.1 nmol/L. The limit of detection and lower limit of quantification were 0.21 and 0.57 nmol/L, respectively. Reciprocal sensitivity was 0.53 nmol/L Sr at A = 0.0044. The intraassay precision was 2.2%, 1.5%, and 1.1% (n = 6) at 4.57, 22.7, and 49.2 nmol/L Sr, respectively. At these concentrations, the interassay precision and recovery were 0.7%, 1.5%, and 1.8% and 100.4%, 99.1%, and 100.6% (n = 12), respectively. The endogenous Sr concentration in human plasma samples was 0.27 +/- 0.07 mumol/L (n = 18). Pharmacokinetic studies in a human volunteer and in rats demonstrated that this procedure was suited for measuring low Sr concentrations and was applicable to small sample volumes.

Adult↗
PubMed1994

Graphite furnace atomic absorption spectroscopic measurement of blood lead in matrix-matched standards.

Now that the level of concern for a toxic blood lead concentration is 0.482 mumol/L (10 micrograms/dL), laboratories must meet new requirements to shorten analysis times and increase accuracy and precision of blood lead determinations. We used a matrix-matching method to estimate the lead concentration in blood by graphite furnace atomic absorption spectroscopy (GFAAS). For CDC proficiency samples and the NIST-Certified Blood Reference standard, the performance of this method compared favorably with that of previously published GFAAS methods and of the anodic stripping voltammetric method routinely used in our laboratory. At lead concentrations of 0.242 mumol/L (5.01 micrograms/dL) and 1.478 mumol/L (30.63 micrograms/dL), within-run CVs were 2.78% and 0.68%, respectively; between-run CVs were 4.9% and 1.35%. In 52 study samples with lead content ranging from 0.097 to 3.812 mumol/L (2 to 79 micrograms/dL), 87% of results by the matrix-modified method were within 0.048 mumol/L (1 microgram/dL) of consensus values.

Calibration↗