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  • Author or Editor: A. Garg x
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Abstract  

Instrumental neutron activation analysis (INAA) has been used for the determination of 27 elements (Ag, Au, Ba, Br, Ce, Co, Cr, Cs, Eu, Fe, Ga, Hg, Hf, K, La, Mn, Na, Sb, Sc, Se Sr, Th, P, Ta, Tb, Zn and Zr) in 15 water samples collected from different sources (reservoirs, well, borewell, sewage tank, river, rain) in and around Nagpur city (central India) including doubly distilled and a sea water sample from Bombay. Sample residues after evaporation were irradiated at a thermal neutron flux of 1012–1013 n·cm–2·s–1 for 10 min, 1d and 1wk and counted using a HPGe detector and an 4k MCA at different intervals. Several environmental standards from NIST (USA), NIES (Japan) and USGS rock were also analysed for quality assurance. Wide variations in elemental concentrations have been observed in water samples from different sources. Most elemental concentrations in drinking water from various sources, are within ISI/WHO limits. Sea water showed very high concentrations of Ba, Cr, Co, Fe, Hg, Sb, Se and Zn. For doubly distilled and rain waters, however, very low elemental concentrations of Ba, Ce, Fe, Sc, Hg, Se, Sr and Th were observed.

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Abstract  

Radiochemical NAA methods have been developed for the simultaneous determination of Fe and Zn in biological samples. The method involves reactor irradiation, dissolution in 3M HCl and solvent extraction followed by counting on a scintillation gamma-ray spectrometer. Iron was separated with aqueous cupferron and extracted into chloroform while Zn was extracted with 2-thenoyl trifluoroacetone (TTA) into methyl isobutyl ketone (MIBK). Reaction conditions such as pH and the effect of solvents and various ions were studied using tracer activities. The methods have been employed for trace level determination of Fe and Zn in NBS, SRMs, Bowen's Kale, IAEA CRMs and other plant leaves.

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Abstract  

Short-term reactor irradiation followed by successive counting over long periods has been used for the nondestructive determination of more the 20 elements in geological and biological samples. The samples, along with USGS standards and NBS SRMs, were irradiated for 5 m, 10 m, 15 m, 1 h, 2.5 h, and 10 h, followed by counting on a Ge/Li/ gamma-ray spectrometer. The technique has been employed for the determination of several major, minor, and trace constituents in geological, biological and environmental samples.

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Abstract  

Human, animal (cow, buffalo and goat) and commercial milk powders (for infants and adults) have been analyzed for 5 minor (Na, K, Mg, Cl and P) and 13 trace elements (Cr, Mn, Fe, Co, Cu, Zn, Cd, Hg, As, Se, Sb, Cs and Br) by instrumental and radiochemical neutron activation. Milk standards NIST SRM 1549 and IAEA A-11 along with diet standards RM 8431 a and IAEA H-9 were also analyzed for quality assurance. The method involves thermal neutron irradiation for 10 m, 1 h, 6 h and 1 week in a reactor followed by high resolution -spectrometry. Concentrations of Fe, Co, Zn, Sb, and Se were also determined by radiochemical solvent extraction. Mean concentrations of Na, K, Mg, P, Cl, Fe, Mn and Cu in human milk (colostrum) are comparable with that of a WHO/IAEA study. It has, however, lower contents of toxic trace elements (Cr, Cd, Hg, Br, Se, Sb and As) compared to breast tissue from the same area. Cow milk is richer in Na, K, Cl, Mn and Se but it has comparable amounts of Mg, Zn, Br, Fe and Sb with respect to breast milk. Significant differences have been observed for elemental concentrations of Na, K, P and Fe in commercial formula milk powders for infants and adults. Infant's milk powders contain all the nutrient elements in balanced amounts required for the higher growth rate of a child.

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Abstract  

A radiochemical solvent extraction method has been developed for the determination of Cr(III) using51Cr tracer. It is based on the complexation of Cr(III) with 8-hydroxyquinoline (oxine) and acetylacetone as mixed ligands at pH 3.8 and extraction in chloroform. Effect of various parameters such as pH, time of equilibration, nature of solvent, quantitative nature, effect of diverse ions has been studied. The method can be used up to 200 ng of Cr.

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Abstract  

Fast neutron-activation methods have been developed for the determination of iron and silicon in USGS and Indian standards and bauxites. Nuclear reactions56Fe/n, p/56Mn and28Si/n, p/28Al were carried out using241Am-Be neutron source and cutting off thermal neutrons with a Cd shield. For Si a cyclic method was adopted due to short half life of28Al /2.3 min/. The methods are non destructive, fast, economic and ideal for bulk analysis of rocks and process control.

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Abstract  

Instrumental Neutron Activation Analysis (INAA) has been employed for the multielemental determination of an IAEA intercomparison standard Hay Powder, V-10 and some edible plant leaves consumed in India. The samples were irradiated with thermal neutrons at a flux 1012 n·cm–2·s–1 in a reactor for 5 minutes, 1, 2, 5, 10 and 15 hours and counted by high resolution -ray spectrometry. Nearly 18 elements have been determined. Good agreement is observed for most of the elements in several NBS standards and the proposed CRM V-10. Some edible vegetable plant leaves have also been analyzed.

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Abstract  

A radiochemical solvent extraction method has been developed for the micro determination of Mo/VI/ using99Mo tracer. It involves removal of99mTc by ethyl methyl ketone /EMK/ and extraction of Mo with tri-n-butyl phosphate /TBP/ from 5M HCl. Different parameters affecting the extraction such as pH dependence, nature of solvent and interferences due to other radionuclides have been studied. The method can be used up to 2 g of Mo.

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Abstract  

A radiochemical solvent extraction method has been developed for the determination of Mn(II) using54Mn tracer. Mn(II) is complexed with 2-thenoyltrifluoroacetone (TTA) at pH 8.5 and extracted in isobutyl methyl ketone (IBMK). Different parameters affecting the extraction, and interferences due to diverse ions have been studied. The method can be used for the determination of Mn in microgram amounts.

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Abstract  

Phosphorus has been determined using the - emitter32P by instrumental neutron activation analysis (INAA) in several NBS and IAEA standards and samples of biological origin such as human and animal blood, cancerous tissue, edible plant leaves, diets, milk samples, etc. The method involves thermal neutron irradiation for 2–10 h in a reactor followed by --counting on an end-window gas flow proportional counter using an aluminium filter. The results are within ±10% of the certified values in most cases.

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