Antimony Pentoxide Research Articles

Elemental analysis of human placenta by neutron irradiation and gamma-ray spectrometry (standard, prompt and fast-neutron)

Human placental tissue from 100 hospitalized deliveries were analysed for Ag, Al, As, Au, B, Ba, Br, Ca, Cd, Cl, Co, Cr, Cs, Cu, F, Fe, I, Hg, K, La, Mg, Mn, Mo, Na, Ni, Rb, S, Sb, Sc, Se, Sn, Sr, Ti, V, W and Zn using a combination of pre-chemical separation of sodium with hydrated antimony pentoxide and instrumental neutron activation analysis. Boron and Si values were determined using prompt gamma-ray and fast-neutron techniques respectively. Analysis of NBS-SRM Bovine Liver 1577 and a ‘pooled standard’ placental tissue for 33 elements showed a good agreement with most coefficients of variation less than or equal to 15%, and recoveries of 91–104%. Symmetrical distributions, were obtained for all elemental placental values. Only Cd(−) and Zn(+) showed statistically significant correlations with birth weight, gestational age and placental weight. The influence of cigarette smoking is considered a major factor in producing elevated cadmium levels in the placental tissue of smokers and passive smokers, and hence lower birth weights.

Determination of uranium and thorium at the sub-ng/g-level in high-purity aluminium by radiochemical neutron activation analysis

A radiochemical neutron activation analysis technique for the determination of uranium und thorium in highpurity aluminium via the indicator radionuclides 239Np and 233Pa, respectively, has been developed. The separation procedure is based on the removal of 24Na on hydrated antimony pentoxide followed by ion-exchange on Dowex-1X8 from HCl/HF and HCl medium. The eluate fraction being of interest for the determination of uranium and thorium contains > 99% of 239Np and 233Pa and, in addition, 11±2% of hafnium and 29±5% of zirconium, and non-detectable fractions of other radionuclides. For a 3-day irradiation of a 100 mg sample at a thermal neutron flux of 1014cm−2s−1 and a decay time of 5 days, the attainable detection limit for both elements is 0.05 ng/g. The method was applied to the analysis of different high-purity aluminium samples, and the results are compared with those obtained in other laboratories.

Neutron activation analysis of aluminium with radiochemical separation of 24Na

In the irradiation of aluminium with fission neutrons, dominant radioactivity of 24Na (t1/2=15.03 h) is produced from the matrix element by fast neutrons via the 27Al(n,α) reaction. The high Compton underground resulting from this matrix radionuclide is a serious limiting factor of the determination of low contents of elemental impurities in aluminium by direct gamma ray spectrometry via indicator radionuclides with t1/2≦3 d. A specific removal of this matrix activity was achieved by adsorption of sodium (> 99%) on hydrated antimony pentoxide from a HCl/HF-medium, while 48 other elements remain in the eluate with yields > 99% and the elements Br, Cs, K, Rb, and Se with yields between 93–98.5%. Applying this radiochemical separation to the analysis of high purity aluminium, the limits of detection could be improved by a factor up to 200. The attainable limits of detection are at the 0.01 ng/g level for Au, Eu and Sc, at the 0.1 ng/g level for

Determination of selected trace metals in scallops by flame atomic absorption spectrometry after removal of sodium on hydrated antimony pentoxide

Hydrated antimony pentoxide is used to remove sodium ion for the determination of trace metals in scallop specimens of Plactopecten magellanicus. The concentrations of Cd, Cr, Co, Cu, Au, Fe, Pb, Mn, Hg, Ni, Ag and Zn were determined in the samples and in a standard reference material. This method yields improved detection limits with simple apparatus.

Studies on the selectivity of Na+ separation on specially prepared hydrated antimony pentoxide

The selectivity of Na+ separation on especially prepared hydrated antimony pentoxide (HAP) was studied with respect to trace elements. For this purpose NaCl samples, doped with 0.5 μg each of altogether 21 selected elements in form of suitable neutron activated compounds, were in relation to practice subjected to column experiments. In some cases trace elements were used in different oxidation states. Considered were elements which are of particular interest for neutron activation analysis. With simultaneous retention of Na+ (DK≥108) Cs, Ba, Sc, La, Ce, Eu, Cr, Mo, Mn, Co, Cu, Ag, Au, Zn, Cd, Hg, and Sb are completely eluted from the HAP column, using 7.5N HCl, whereby Cs and to some extent Ba and Sc in comparison to the elements mentioned above required a higher elution volume. Rb, Se and As on the contrary were almost quantitatively retained on HAP column, W partly as WO 4 2− . The scope of validity of the results will be discussed.

Preparation of antimony oxide catalysts by interaction of Sb2O5·nH2O with some cations and anions

The possibility of sorptional binding of components has been established for antimony oxide catalysts obtained by mixing hydrated antimony pentoxide with solutions of compounds in anionic and cationic forms.

Determination of short-lived activation products in neutron-irradiated sodium through application of hydrated antimony pentoxide

A method for the determination of short-lived activation products in neutron-irradiated sodium is described. It is based on hydrolysis of sodium with methanol, separation of Na+ with specially prepared antimony pentoxide (HAP) possessing very high selectivity and capacity, and subsequent gamma-spectroscopic measurement of the activation products.

Studies on the preparation of hydrated antimony pentoxide (HAP) to separate Na+ in the field of radioanalytical investigations

Hydrated antimony pentoxide with favourable chemical and mechanical properties could be produced from an aqueous suspension of antimonic acid by a two stage drying process.

A Study of the Adsorption of22Na from acid solutions on Hydrated Antimony Pentoxide

The technique of sodium removal from acid solutions with Hydrated Antimony Pentoxide (HAP) has been used as a separation and preconcentration step in the determination of trace elements in many matrices. In trying to understand the mechanism of the sodium retention process the studies have revealed that although the retained sodium is difficult to elute, it can undergo an exchange process with dilute solutions of NaCl in hydrochloric acid. Hydrogen ions play a role in this exchange process. 7 references, 2 figures.

Antimoniosis: a particular form of pneumoconiosis. I. Etiology, clinical and X-ray findings.

The occupational exposure, clinical findings, lung function and radiological characteristics of 51 workers in an antimony smelting plant are presented. The workers were exposed to the airbone dust containing a high concentration of antimony trioxide (up to 88%) and antimony pentoxide. A particular X-ray picture was characterized by numerous small opacities densely distributed in the middle and lower lung fields, opacities of p, pinhead type. Sporadically pq type was seen, but never r type nor massive fibrosis (pmf). The pneumoconiotic changes developed after at least one decade of work. Nothing particular in clinical findings and lung function could be distinguished from other types of simple pneumoconioses. This pneumoconiosis is called--antimoniosis. No systemic manifestation of antimony oxide intoxication was found, with the exception of skin changes, "antimony dermatosis".

Determination of some toxic trace metals in Nigerian river and harbor water samples by neutron activation analysis

The determination of As, Cd, Cr, Hg, Mn, Mo, Ni, Sb, and Se in two Nigerian rivers and two Nigerian harbor waters is described. The water samples were preconcentrated by both evaporation at room temperature and freeze evaporation under reduced pressure. Postirradiation chemical separation of sodium, using hydrated antimony pentoxide (HAP) in 6M HCl, and of bromine, by oxidation with KMnO4 and subsequent removal by extraction with CHCl3, was employed. The measured concentrations of these elements in some water samples, which are relatively high, can be attributed to local pollution.

Determination of trace elements in particulate and soluble fractions of seawater by neutron activation analysis

Determination of trace element concentrations in marine samples is of considerable interest in studying diverse types of oceanic pollution sources, mode of transport and residence times of pollutants in seawater, and in revealing interactions that may exist among elements in suspended particulate and soluble fractions of seawater. Neutron activation analysis (NAA) methods are being investigated in this laboratory for measuring multi-element concentrations of oceanic suspended particulate matter (SPM) and seawater. An instrumental NAA (INAA) method has been developed for determining Al, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Eu, Fe, Hf, Hg, I, K, La, Lu, Mg, Mn, Na, Nd, Rb, Sb, Sc, Se, Sm, Sr, Th, Ti, V and Zn in microgram quantities of oceanic SPM. The method consists of three sequential irradiations at two different neutron fluxes and subsequent counting after five decay periods using high-resolution detectors. The method for determining trace elements in seawater involves preirradiation separations of Br and Cl using nitric acid and hydrogen peroxide and of Na with hydrated antimony pentoxide. Concentrations of Ag, Ca, Co, Cr, Fe, La, Lu, Mn, Mo, Sm, Sr, Ti, V and Zn in seawater have been measured. Details of analytical methodologies for determining trace elements in both suspended particulate and soluble fractions of seawater are presented.

Removal of sodium and chlorine from seawater prior to neutron activation analysis for trace elements

A neutron activation analysis (NAA) method has been developed for the determination of 14 elements in seawater samples. The method consists of pre-irradiation separations of interfering elements, viz. Na with hydrated antimony pentoxide, leached Sb using either acid aluminum oxide or tin dioxide, and Cl and Br with a mixture of nitric acid and hydrogen peroxide, followed by 3 different irradiation, decay and counting periods. Concentrations of Ag, Co, Cr, Cu, Fe, La, Lu, Mn, Mo, Sc, Sm, Ti, V and Zn have been measured and compared with those obtained by an independent preconcentration method. Precision and limits of detection and determination have been evaluated.

Determination of manganese in tissues by neutron activation analysis using an antimony pentoxide column

A rapid and accurate method is presented for the determination of manganese in biological samples, using neutron activation analysis. Biological samples were irradiated at 5000 kW for 30 min. The samples were ashed on a hot plate with 14 mol/l HNO 3 and 6 mol/l HClO 4, and resolved in 1 mol/1 HClO 4. 24Na and 42K were removed by passing each sample through an antimony pentoxide column. 54Mn was added as a tracer to calculate the ratio of manganese recovered by the separation procedure. Recovery was over 90%. This method was applied in order to determine manganese in various tissues. In the cervical spinal cord of the controls, the mean manganese concentrations in the anterior horn, the lateral and the posterior columns were 1.14, 1.06 and 0.90 ng/mg of dried tissue, respectively. In two cases if amyotrophic lateral sclerosis the manganese concentrations in the cervical spinal cord were elevated, particularly in the anterior horn and the lateral column.

Electrical properties of SnO 2 films on various glass substrates

The electrical resistivity of stannic oxide film can be lowered by incorporating about 5 mol% antimony pentoxide. It has been found that the resistivity varies by nearly one order of magnitude, depending on the kind of glass substrate. The change in mobility is responsible for the resistivity change. The importance of structural tightness has been emphasized on the basis of chemical, structural and diffraction analyses.

Determination of cesium and potassium in marine species by neutron activation analysis

Cesium and potassium were determined in muscle-tissues of squid, dover sole, albacore, and bocaccio by NAA. Potassium was measured instrumentally, while cesium was radio-chemically separated. For the separation of cesium, hydrated antimony pentoxide (HAP) was used to retain24Na, and ammonium molybdophosphate (AMP) was used to absorb quantitatively the radiocesium,134mCs. The cesium and potassium contents were based on measuring the short-lived radionuclide of cesium, 2.90 h-134mCs, and 12.4 h-42K. The mean concentrations of cesium found, based on 3–4 replicate measurements for each fish, were: 4.18±0.32 ng/g squid, 11.51±0.30 ng/g dover sole, 43.64±1.03 ng/g albacore, and 56.85±3.61 ng/g bocaccio. The mean concentrations of potassium found were: 1.28±0.10 mg/g squid, 2.78±0.29 mg/g dover sole, 3.69±0.06 mg/g albacore, and 4.18±0.10 mg/g bocaccio.

Synthetic Inorganic Ion-Exchange Materials. XXVII. A Study on Ion-Exchange Selectivity in Crystalline Antimonic(V) Acid and Hydrated Antimony Pentoxide for Various Metal Ions in Nitric Acid Media

Abstract A comparative study of ion-exchange selectivity was carried out between crystalline antimonic(V) acid (C-SbA) and hydrated antimony pentoxide (HAP). The extended plate theory was applied for evaluating the values of distribution coefficients of various metal ions on HAP from the retention results reported by Girardi et al. The results indicate that the ion-exchange selectivity of C-SbA is essentially compatible with that in HAP for 17 of 20 metal ions.

Multi-element analysis of blood for trace metals by neutron activation analysis

Fourteen elements can be rapidly determined in whole blood by the neutron activation analysis procedure described. Three of these (Ag, Cl, Se) are measured after a 10-s irradiation and eleven others (Al, Ba, Br, Ca, Cu, I, Mg, Mn, Mo, Rb, V) are determined by a 180-s irradiation of a 1-cm 3 sample of whole blood after destruction of organic matter and removal of sodium by hydrated antimony pentoxide. A further 13 elements (As, Au, Co, Cr, Cs, Fe, Hg, K, Na, Ni, Sb, Sc, Zn) are determined after overnight irradiation in the SLOWPOKE reactor.

Determination of Trace Elements in the River Aare (Switzerland) by Neutron Activation Techniques

Abstract More than 20 trace and minor elements were determined in water samples and in the suspended load of the river Aare (Switzerland) using a simple sample preparation technique and subsequent instrumental neutron activation analysis. The water samples were irradiated without preconcentration. The interfering activity of 24Na was eliminated with hydrated antimony pentoxide. The trace elements were co-precipitated as sulfides and hydroxides and were analyzed on Ge(Li)gamma-ray spectrometers. Particulate matter was filtered off in the field, irradiated and assayed by γ-ray spectroscopy. Main results: (a) the concentrations of all the elements investigated are much lower than WHO-limits for drinking water; (b) human activities are responsible for an increase of some elements along the river: (c) concentrations of dissolved trace elements are anticorrelated to the amount of water; (d) concentrations of trace elements in particulates (μg/l) are correlated to the amount of water: (e) significant correlation...

A new technique in neutron activation analysis of Na/K ratios of fluid inclusions and its application to the gold–quartz veins at the O'Brien mine, Quebec, Canada

A new analytical technique which employs hydrated antimony pentoxide to selectively remove Na from Na–K–Cl mixed fluids was successfully tested. With this technique, the uncertainty in the K determination of inclusion fluids by neutron activation analyses can be reduced to less than ± 10% compared to greater than ± 20% uncertainty which is typical in the conventional techniques.Na/K ratios of fluid inclusions in 14 quartz samples from gold–quartz veins at the O'Brien mine. Quebec, Canada were determined using this technique. The Na/K atomic ratio of the samples ranges from 0.9 ± 0.1 to 24.3 ± 3.9. Optical examinations of the fluid inclusions indicate that the variation in the Na/K ratios is caused by the presence of varying proportions of four different types of fluid inclusions: type I (pregold mineralization fluids: CO2 rich), type II (gold mineralizing fluids showing evidence of boiling at temperatures of 380°–300 °C), type III (postgold mineralization fluids; vapor – liquid two phase inclusions), and type IV (postgold mineralization fluids; halite bearing), Type II fluid inclusions appear to have Na/K atomic ratios of approximately 1.0, while type IV inclusions show Na/K ratios of over 24.