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Query: UMLS:C0205700 (ash)
 15,125 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A method was developed to analyze various calcium supplements for Ca and Pb content. The analysis involves a dry ash of the supplements followed by wet digestion. The Pb is determined by graphite furnace atomic absorption spectrophotometry (GFAAS). Analysis of Ca is by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Ca supplements fortified with Pb at levels ranging from 0.25 to 10.0 micrograms/g yielded recoveries ranging from 82.7 +/- 4.2 to 105.0 +/- 1.7%. To test accuracy, the method was applied to National Institute of Standards and Technology standard reference materials (NIST SRMs) 1572 citrus leaves and 1486 bone meal. GFAAS analysis of SRM 1572 averaged 13.1 +/- 0.6 micrograms Pb per g (certificate value, 13.3 +/- 2.4 micrograms Pb per g), and analysis of SRM 1486 averaged 1.34 +/- 0.11 micrograms Pb per g (certificate value, 1.335 +/- 0.014 micrograms Pb per g). ICP-AES analysis of SRM 1572 averaged 3.12 +/- 0.01% Ca (certificate value, 3.15 +/- 0.10% Ca by weight), and analysis of SRM 1486 averaged 27.63 +/- 0.27% Ca (certificate value, 26.58 +/- 0.24% Ca). The method's limit of quantitation (LOQ), on supplement Ca basis and a 1 g sample, averaged 0.75 micrograms Pb per 1 g Ca for supplements containing 9 to 35% Ca by weight. At a Pb level of 0.663 micrograms/g Ca, the reproducibility relative standard deviation (RSDr) averaged 7.3% and the repeatability relative standard deviation (RSDR) averaged 8.0%. It is recommended that the method be studied collaboratively.
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PMID:Analysis of calcium and lead in calcium supplements by inductively coupled plasma-atomic emission spectrometry and graphite furnace atomic absorption spectrophotometry. 795 Apr 30

A simple method based on inductively coupled plasma mass spectrometry (ICP-MS) was developed to identify exposure to depleted uranium by measuring the isotopic composition of uranium in urine. Exposure to depleted uranium results in a decreased percentage of 235U in urine samples causing measurements to vary between natural uranium's 0.72% and depleted uranium's 0.2%. Urine samples from a non-depleted uranium exposed group and a suspected depleted uranium exposed group were processed and analyzed by ICP-MS to determine whether depleted uranium was present in the urine. Sample preparation involved dry-ashing the urine at 450 degrees C followed by wet-ashing with a series of additions of concentrated nitric acid and 30% hydrogen peroxide. The ash from the urine was dissolved in 1 M nitric acid, and the intensity of 235U and 238U ions were measured by ICP-MS. After the samples were ashed, the ICP-MS measurements required less than 5 min. The 235U percentage in individuals from the depleted uranium exposed group with urine uranium concentrations greater than 150 ng L(-1) was between 0.20%-0.33%, correctly identifying depleted uranium exposure. Samples from the non-depleted uranium exposed individuals had urine uranium concentration less than 50 ng L(-1) and 235U percentages consistent with natural uranium (0.7%-1.0%). A minimum concentration of 14 ng L(-1) uranium was required to obtain sufficient 235U to allow calculating a valid isotopic ratio. Therefore, the percent 235U in urine samples measured by this method can be used to identify low-level exposure to depleted uranium.
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PMID:Determination of the isotopic composition of uranium in urine by inductively coupled plasma mass spectrometry. 1064 80

1-Methyl-2-pyrrolidinone (NMP) was used to extract samples of wood (forest residue) and coal; the extracts were analysed by inductively coupled plasma mass spectrometry (ICP-MS) using two different sample preparation methods, in order to identify trace elements associated with the organic part of the samples. A sample of fly ash was similarly extracted and analysed in order to assess the behaviour of the mineral matter contained within the wood and coal samples. 32% of the biomass was extracted at the higher temperature and 12% at room temperature while only 12% of the coal was extracted at the higher temperature and 3% at room temperature. Less than 2% of the ash dissolved at the higher temperature. Size exclusion chromatograms of the extracts indicated the presence of significant amounts of large molecular mass materials (>1000 mu) in the biomass and coal extracts but not in the ash extract. Trace element analyses were carried out using ICP-MS on the acid digests prepared by 'wet ashing' and microwave extraction. Sixteen elements (As, Ba, Be, Cd, Co, Cr, Cu, Ga, Mn, Mo, Ni, Pb, Sb, Se, V and Zn) were quantified, in the samples before extraction, in the extracts and in the residues. Concentrations of trace elements in the original biomass sample were lower than in the coal sample while the concentrations in the ash sample were the highest. The major trace elements in the NMP extracts were Ba, Cu, Mn and Zn from the forest residue; Ba, Cu, Mn, Pb and Zn from the coal; Cu and Zn from the ash. These elements are believed to be associated with the organic extracts from the forest residue and coal, and also from the ash. Be and Sb were not quantified in the extracts because they were present at too low concentrations; up to 40% of Mn was extracted from the biomass sample at 202 degrees C, while Se was totally extracted from the ash sample. For the forest residue, approximately 7% (at room temperature) and 45% (at 202 degrees C) of the total trace elements studied were in the extract; for the coal, approximately 8% (at room temperature) and 23% (at 202 degrees C) were in the extract. For the ash, only 1.4% of the trace elements were extracted at 202 degrees C, comprising 25% of Cd but less than 1% of Pb.
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PMID:Identification of organically associated trace elements in wood and coal by inductively coupled plasma mass spectrometry. 1070 33

The concentration of As, Cr and Ni and their speciation (As3+;5+, Cr3+;6+ and Ni0;2+) in milled coal, bottom ash and ash collected by electrostatic precipitator (ESP) from a coal fired-power plant in western Canada were determined using HGAAS, ICP-AES and XANES. The chemical fractionation of these elements was also determined by a sequential leaching procedure, using deionized water, NH4OAC and HCI as extracting agents. The leachate was analyzed by ICP-AES. Arsenic in the milled coal is mostly associated with organic matter, and 67% of this arsenic is removed by ammonium acetate. This element is totally removed from milled coal after extraction with HCI. Arsenic occurs in both the As3+ and the As5+ oxidation states in the milled coal, while virtually all (>90%) of the arsenic in bottom ash and fly ash appears to be in the less toxic arsenate (As5+) form. Both Ni and Cr in the milled coal are extracted by HCI, indicating that water can mobilize Ni and Cr in an acidic environment. The chromium is leached by water from fly ash as a result of the high pH of the water, which is induced during the leaching. Ammonium acetate removes Ni from bottom ash through an ion exchange process. Chromium in milled coal is present entirely as Cr3+, which is an essential human trace nutrient. The Cr speciation in bottom ash is a more accentuated version of the milled coal and consists mostly of the Cr3+ species. Chromium in fly ash is mostly Cr3+, with significant contamination by stainless-steel from the installation itself.
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PMID:Monitoring the species of arsenic, chromium and nickel in milled coal, bottom ash and fly ash from a pulverized coal-fired power plant in western Canada. 1125 1

Because stabilization of arsenite in water samples during transit and storage is troublesome, this work deals with a method to prevent this by on-site selective coprecipitation of arsenite with dibenzyldithiocarbamate and recovery of the coprecipitate by filtration through a 0.45-microm membrane filter. In the laboratory arsenic on the filter is quantitatively released by oxidation of arsenite to arsenate with H2O2 (6%) in alkaline medium (8 mmol L(-1) NaOH) at elevated temperature (85 degrees C) for 30 min followed by ultratrace determination by routine HGAFS and ICP-MS. It is shown that arsenate contamination of the coprecipitate is so low that arsenate concentrations three orders of magnitude higher than the arsenite concentration do not interfere; this is essential, because arsenate is usually the dominant arsenic species in water. Because significant preconcentration can be achieved in the solution obtained from the leached filter (normally a factor 20 but easily increased to 100) very low detection limits can be obtained (only limited by the purity of the materials and the cleanliness of working); a realistic limit of determination is 0.01 microg L(-1) arsenite. The procedure was used for the determination of arsenite in two ground waters from an ash depository site in the Salek valley (Slovenia). The matrix contained some elements at very high levels but this did not impair the efficiency of arsenite coprecipitation. The results obtained by use of HGAFS and ICP-MS were not significantly different at the 5% level for sub-microg L(-1) arsenite concentrations.
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PMID:Determination of ultratrace dissolved arsenite in water--selective coprecipitation in the field combined with HGAFS and ICP-MS measurement in the laboratory. 1149 65

Metals are released in effluents of most of combustion processes and are under intensive regulations. To improve our knowledge of combustion process and their resulting emission of metal to the atmosphere, we have developed an approach allowing usto distinguish between gaseous and particulate state of the elements emitted. This study was conducted on the emission of volatile metallic species emitted from a coal combustion plant where low/medium volatile coal (high-grade ash) was burnt. The occurrence of volatile metal species emission was investigated by cryofocusing sampling procedure and detection using low-temperature packed-column gas chromatography coupled with inductively coupled plasma-mass spectrometry as multielement detector (LT-GC/ICP-MS). Samples were collected in the stack through the routine heated sampling line of the plant downstream from the electrostatic precipitator. The gaseous samples were trapped with a cryogenic device and analyzed by LT-GC/ICP-MS. During the combustion process, seven volatile metal species were detected: three for Se, one for Sn, two for Hg, and one for Cu. Thermodynamic calculations and experimental metal species spiking experiments suggest that the following volatile metal species are present in the flue gas during the combustion process: COSe, CSSe, CSe2, SeCl2, Hg0, HgCl2, CuO-CuSO4 or CuSO4 x H2O, and SnO2 or SnCl2. The quantification of volatile species was compared to results traditionally obtained by standardized impinger-based sampling and analysis techniques recommended for flue gas combustion characterization. Results showed that concentrations obtained with the standard impinger approach are at least 10 times higher than obtained with cryogenic sampling, suggesting the trapping microaerosols in the traditional methods. Total metal concentrations in particles are also reported and discussed.
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PMID:Volatile metal species in coal combustion flue gas. 1199 67

Analytical techniques used to examine the chemical speciation of multiple trace elements are important for the investigation of biological systems. Size exclusion chromatography (SEC) coupled to ICP-MS was used to investigate the speciation of Se, As, Cu, Cd and Zn in tissue extracts from a largemouth bass (Micropterus salmoides) collected from a coal fly ash basin and results were compared to a largemouth bass collected at a reference site. Using a Biosil SEC column, with an effective separation range of 100-7 KDa, Cu, Zn and Cd were shown to be bound to metallothionein (MT) in the liver, gill and, to a lesser extent, gonad tissue extract. In liver, muscle and gill of the ash basin bass, Se was predominantly present as low molecular weight species. Only in the gonad extract was the major fraction of Se associated with high molecular weight species. For the liver and gill extracts, further SEC-ICP-MS on a column with an effective separation range of 7000-500 Da was performed, but Se species still eluted near the total volume of the column suggesting a low molecular weight organic or inorganic species. Ion chromatography (IC)-ICP-MS using an AS7 column and HNO(3) gradient elution indicated that the Se and As species in the liver and gill extracts had similar retention times but these retention times did not correspond to retention times for As(III), As(V), dimethylarsenate, arsenobetaine, Se(IV), Se(VI), seleno-methionine, or seleno-cystine.
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PMID:Trace element speciation in largemouth bass ( Micropterus salmoides) from a fly ash settling basin by liquid chromatography-ICP-MS. 1232 38

Trace metal composition of winter snowpack, snow-melt filter residues and top-soil samples were determined along three transects through industrial towns in the Usa basin, North-East Russia: Inta, Usinsk and Vorkuta. Snow was analysed for Ag, Al, As, Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr and Zn using ICP-MS (Ca and K by F-AAS for Vorkuta only), pH and acidity/alkalinity. Filter residues were analysed for: Al, Ba, Ca, Cd, Cu, K, Mg, Mn, Ni, Pb, Sr and Zn using F-AAS and GF-AAS; top-soil samples were analysed for Ba, Cu, Mg, Mn, Na, Ni, Pb, Sr, Zn using F-AAS. Results indicate elevated concentrations of elements associated with alkaline combustion ash around the coal mining towns of Vorkuta and Inta. There is little evidence of deposition around the gas and oil town of Usinsk. Atmospheric deposition in the vicinity of Vorkuta, and to a lesser extent Inta, added significantly to the soil contaminant loading as a result of ash fallout. Acid deposition was associated with pristine areas whereas alkaline combustion ash near to emission sources more than compensated for the acidity caused by SO2.
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PMID:Anthropogenic metal enrichment of snow and soil in north-eastern European Russia. 1247 56

A new method is described for the analysis of whole coal for the major ash forming elements by ICP-AES. The major ash forming elements were extracted with HF and HNO3 in an ultrasonic water bathe. The best proportion of the acid and the time of extraction were studied. Compared with the ash content of coal, the extraction ratio is more than 95%. Recovery ratio is between 96%-104%. RSD of extraction and determination is less than 4% (n = 9).
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PMID:[Acid extraction of coal for the determination of major ash forming elements by ICP-AES]. 1294 63

Fly ash has been regarded as hazardous because of its high adsorption of toxic organic and/or inorganic pollutants. Fly ash is also known to have broad distributions of different chemical and physical properties, such as size and density. In this study, fly ash emitted from a solid waste incinerator was pre-fractionated into six sub-populations by use of gravitational SPLITT fractionation (GSF). The GSF fractions were then analyzed by sedimentation field-flow fractionation (SdFFF) and ICP-AES. SdFFF analysis showed the fly ash has a broad size distribution ranging from a few nanometers up to about 50 microm. SdFFF results were confirmed by electron microscopy. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analysis of the GSF fractions showed the fly-ash particles contain a variety of inorganic elements including Ca, Si, Mg, Fe, and Pb. The most abundant in fly ash was Ca, followed by Si then Mg. No correlations were found between trace element concentration and particle size.
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PMID:Size-based analysis of incinerator fly ash using gravitational SPLITT fractionation, sedimentation field-flow fractionation, and inductively coupled plasma-atomic emission spectroscopy. 1468 52


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