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A method for determining atmospheric diborane in concentrations higher than 1/10 of TLV, i.e., 0.01 ppm, has been developed using the adsorption sampling method. Silica gel impregnated with potassium permanganate, synthetic resin activated carbon impregnated with or without mercury(II) chloride and activated carbon impregnated with chromate salt showed adsorption capacities larger than 18 l of 3 ppm diborane test gas when the test gas was drawn at 300 ml/min. Complete desorption of the adsorbed diborane was possible only from silica gel impregnated with potassium permanganate into a hydroxylamine hydrochloride solution. As methods for determining the desorbed boron, both the chromotropic acid-HPLC method and ICP-AES were applied. The former was more sensitive, but the latter was less influenced by coexistent substances. The most sensitive and reproducible procedure for diborane determination was as follows: diborane is collected with silica gel impregnated with potassium permanganate (0.05% (w/w)) and desorbed into hydroxylamine hydrochloride solution (400 micrograms/ml) followed by the determination of boron by the chromotropic acid-HPLC method. When diborane in 3 l of 0.1 ppm test gas was collected, the desorption efficiency was 105.3% with an RSD of 13.5%. The limit of quantitation of this method was 0.0026 ppm in 3 l air. Much lower concentrations can be determined by sampling larger amounts of air.
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PMID:Determination of diborane by adsorption sampling using modified silica gel and the chromotropic acid-HPLC method. 131 78

1. The interaction between As and three toxic metals (Cd, Ni and Pb) and Cu (an essential trace metal) in the kidney was investigated in the rat by feeding diets containing various concentrations of As whilst maintaining constant concentrations of the other elements. After 1, 3, 7 and 15 weeks of feeding, metal contents in the renal cortex and medulla, red blood cells and plasma were determined by atomic emission spectrometry (ICP-AES). 2. As accumulated in the whole kidney, whereas Cu accumulated only in the cortex. Accumulation of Cu was found to depend on the feeding period and dietary As concentration. 3. As was also accumulated in red blood cells, where saturation was found at 550 micrograms As g-1 cells. 4. Although Cd was also accumulated in the cortex, its accumulation was independent of the dietary As concentration. Ni and Pb were not detected by ICP-AES. 5. Chromatography of the supernatants from cortical homogenates of control and As-treated rat kidney suggested that Cu accumulated in renal metallothionein (MT). Its accumulation in this fraction was independent of that of Cd, indicating that the As-Cu interaction was not a result of MT induction, but rather that it might result from altered renal handling of Cu with subsequent incorporation into MT.
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PMID:Arsenic-copper interaction in the kidney of the rat. 135 44

A sensitive assay using inductively coupled plasma atomic emission spectroscopy (ICP-AES) has been applied to the measurement of trace elements in diaspirin cross-linked hemoglobin (DCLHb) solutions. Calcium, magnesium, zinc and iron were the only elements detected at greater than background levels. Ag, Al, As, B, Ba, Bi, Cd, Co, Cr, Cu, Mn, Mo, Pb, Sb, Se, Si, Sr, Ti, and V were present at concentrations either equal to the acid blanks or were not detected. Detection of non-heme iron (not incorporated into the hemoglobin porphyrin ring) in a 10 g/dL hemoglobin solution required the development of a special protocol. In this protocol a chelator, DTPA, was added to hemoglobin solutions to complex with both free and non-specifically bound non-heme iron. The resulting iron:DTPA complexes were separated from the hemoglobin molecules by ultrafiltration and the ultra-filtrate analyzed by ICP-AES. A modification of this assay in which the DTPA was omitted was used to measure the free non-heme iron in solution. Typical concentrations of chelatable (free and non-specifically bound) and solution (free) non-heme iron in DCLHb production lots at the completion of manufacture were 0.5-1.0 ppm and 0.1-0.3 ppm, respectively.
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PMID:Trace element analyses of diaspirin cross-linked hemoglobin solutions. 139 63

Sequential MR imaging with gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) and sequential measurements of plasma Gd-DTPA concentration by inductively coupled plasma atomic emission spectroscopy (ICP-AES) were used to estimate the blood-to-tissue transport coefficient (Ki) in the 36B-10 rat glioma model. For these measurements, tissue Gd-DTPA concentration was estimated from tumor enhancement by correlation with calibration measurements obtained by ICP-AES analysis of tumor tissue. The 14 animals for which Ki was calculated can be grouped into those imaged at 11 days following tumor implantation, at 13-18 days, and at 20 days. The mean (+SEM) Ki values for these groups were 1.1 + 0.24, 9.2 + 0.8, and 13.4 + 1.7 ml/kg-min, respectively. These results correspond well with published data obtained by quantitative autoradiography. It is concluded that frequent sequential imaging and a graphical approach to Ki calculation are promising methods for determining the blood-to-tissue transport coefficient noninvasively by contrast-enhanced MRI.
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PMID:Measurement of blood-brain barrier permeability in a tumor model using magnetic resonance imaging with gadolinium-DTPA. 143 11

Based on the recent development of analytical methods, sensitive systems for the analysis and speciation of selenium and arsenic have been established. A palladium addition technique was developed for the accurate determination of selenium in biological samples using graphite furnace atomic absorption analysis. For the speciation of the elements, combined methods of HPLC either with ICP-AES or with ICP-MS were found to work well. These systems were applied to the elucidation of the chemical form of the elements in natural samples. Some chemical properties of the selenium-mercury complex in dolphin liver were elucidated: i.e., it was a cationic, water-soluble, low molecular weight compound containing selenium and mercury in a 1:1 molar ratio, and was shown to be different from a known selenium-mercury complex, bis(methylmercuric)selenide. The major selenium compound excreted in human urine was revealed to be other than any of those previously identified (TMSe, selenate, and selenite). TMSe, a suspected major metabolite in urine, was found, if at all, in low levels. The major water-soluble, and lipid-soluble arsenic compounds in a brown seaweed, U. pinnatifida (WAKAME), were rigorously identified, and the results were compared with other data on marine algae and animals. The major organic arsenic compounds (termed "arseno-sugars") in marine algae commonly contain 5-deoxy-5-dimethylarsinyl-ribofuranoside moiety. There are various kinds of arseno-sugar derivatives containing different side-chains attached to the anomeric position of the sugar, and the distribution of each arsenic species seems to be related to algal species. The arseno-sugar (A-XI) is present in every alga so far examined, is metabolized to lipids, and possibly may play some specific role in the algal cells. On the other hand, the major arsenic compound in fish, crustacea and molluscs has been identified as arsenobetaine, which is an arseno-analog of glycinebetaine, a very common osmo-regulator in living organisms. Arsenobetaine is not detected in marine algae while arseno-sugars are not present in marine animals except for some molluscs which contain both compounds in considerable amounts. Arsenobetaine is present in the urine of human beings who have eaten foods derived from marine animals.
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PMID:Selenium and arsenic in biology: their chemical forms and biological functions. 144 44

Arsenobetaine and arsenocholine are considered to be non-toxic and are present as a relatively large proportion of total arsenic in seafoods, and they do not respond to hydride generation. The present study describes the effect of seafood consumption on the urinary concentration of hydride-generating arsenic compounds measured by a newly developed flow injection atomic absorption spectrometric (FI-AAS) method. Consumption of plaice, pighvar and tunny resulted in a 2-fold increase, and consumption of mussels produced a 6-fold increase in the urinary level of hydride-generating arsenic compounds. Hence, a person who has consumed mussels may be suspected of being occupationally or environmentally exposed, if the level of consumption of this seafood is unknown. As the FI-AAS method cannot be used to detect arsenobetaine and arsenocholine, the observed increase in urinary concentration of hydride-generating arsenic compounds after consumption of seafood must originate either from hydride-generating arsenic compounds in the seafood or from degraded arsenobetaine or arsenocholine. The present study has demonstrated that both arsenobetaine and arsenocholine are unstable when incubated in daylight in the presence of hydrogen peroxide, i.e., an oxidizing environment. Hence, it is tempting to speculate that arsenobetaine could be converted into hydride-generating arsenic compounds during storage or cooking of seafood. The feasibility of speciation methods based on high-performance liquid chromatographic (HPLC) separation and on-line analysis by inductively coupled plasma atomic emission spectrometry (ICP-AES) and FI-AAS was also investigated. The FI-AAS system is approximately 35 times more sensitive to the hydride-generating arsenic species than the ICP-AES system.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of seafood consumption on the urinary level of total hydride-generating arsenic compounds. Instability of arsenobetaine and arsenocholine. 158 Apr 19

A study was undertaken to determine the average values for elements in normal human brain (11 individuals, age group 65-75). Twelve brain parts were selected from both hemispheres. Determinations were carried out by NAA and ICP-AES. The main elements (Na, K, Mg, Ca, Fe, P, S) and trace elements (Al, B, Co, Cr, Cu, Mn, Ni, Pb, Zn) were investigated. Quality control was ensured by using NBS Bovine Liver SRM. The results obtained with independent methods were compared, and the data show a good correlation. On the basis of these investigations, the regional distribution of elements can be given.
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PMID:Determination of main and trace element contents in human brain by NAA and ICP-AES methods. 170 77

In this article, the duplication portion technique was used to determine the daily intakes of selenium and ten other elements in the 24-h total diets collected in the typical Kashin-Beck endemic areas, i.e., Shanxi Province and Inner Mongolia Autonomous of China. The contents of Ca, Mg, Cu, Fe, Zn, Mn, Al, Sr, Ba, and P in freeze-dried samples were determined by ICP-AES. Se was determined by differential pulse catalytic polarography. The average Se contents in total diets of Shanxi Kashin-Beck endemic and nonendemic areas were 0.009 and 0.021 micrograms/g (dry weight), respectively (P less than 0.001), corresponding to the daily intakes for Se of 4.6 and 10.5 micrograms. After the Se-supplemented fertilizer was applied (225 g of Na2SeO3/ha), the average Se content in total diets of Kashin-Beck disease area was increased to 0.0336 micrograms/g, which corresponded to the average daily intake for Se of 16.8 micrograms. In Inner Mongolia Kashin-Beck endemic and nonendemic areas, the average Se contents in total diets were 0.006 and 0.017 micrograms/g, respectively (p less than 0.001), corresponding to the average daily intakes for Se of 3 and 8.5 micrograms. The contents of other ten elements in total diets in endemic and nonendemic areas were reported and compared.
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PMID:Selenium in Kashin-Beck disease areas. 172 71

A novel approach for determination of phytic acid in cereals has been applied in 2 traditional methods. In the first, phytic acid in a sample extract is first separated and concentrated by ion-exchange chromatography. The phytic acid concentrate is then quantitatively determined as phosphorus by inductively coupled plasma atomic emission spectrometry (ICP-AES). In the second method, extracted phytic acid is first precipitated by FeCl3 solution. The complexed iron is converted to ferric hydroxide by adding NaOH, thus releasing phytic acid as soluble sodium phytate. Phytate is then quantitatively determined as phosphorus by ICP-AES. In these methods, both the difficult acid digestion and the spectrometric determination of phosphorus found in traditional methods are eliminated by using ICP-AES. This results in a method that is simpler, faster, and more accurate than earlier procedures.
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PMID:Determination of phytic acid in cereals using ICP-AES to determine phosphorus. 202 74

Speciation of inorganic lead (Pb2+) and several trialkyllead species (trimethyllead chloride [TML], triethyllead chloride [TEL], and triphenyllead chloride [TPhL]) is investigated using high-performance liquid chromatography (HPLC) with detection by both inductively coupled plasma emission spectroscopy (ICP-AES), and inductively coupled plasma mass spectrometry (ICP-MS). Reversed-phase, ion-pairing, and ion-exchange HPLC modes are studied. Optimal chromatographic conditions for ICP-AES detection include a reversed-phase separation utilizing a step gradient from 10 to 70% methanol. However, the gradient has been found to destabilize the plasma when using ICP-MS detection. An isocratic separation with a 30% methanol mobile phase has been found to be the best compromise between plasma stability and chromatographic resolution. Detection limits using ICP-MS detection are 3 orders of magnitude improved over ICP-AES detection.
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PMID:Lead speciation by HPLC-ICP-AES and HPLC-ICP-MS. 206 99


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