Authors:P. Melnikov, V. A. Nascimento, and L. Z. Zanoni Consolo
Gallium most commonly enhances the calcium and phosphorus content of bone and has direct noncytotoxic effects on osteoclasts at markedly low doses [ 1 ]. Its future usage, in the form of gallium nitrate, will
A sensitive, simple and time-saving method has been developed for the neutron activation analysis of gallium at concentrations
around 10−4 ppm in biological tissues. After a 24-hour irradiation in a thermal neutron flux of 2.8·1013 n·cm−2·s−1 and a purification by ion-exchange chromatography to eliminate troublesome elements such as sodium, iron and copper, the72Ga activity is measured with enough accuracy for the method to be applicable in animal physiology and clinical toxicology.
Instrumental neutron activation analysis (INAA) has been applied to obtain useful data on impurity concentrations in ultra-pure materials whose matrix elements are strongly activated and create severe interference for several weeks after irradiation. An analytical procedure has been developed and used to determine Sc, Fe, Co, Zn, Se, Zr, Ag, In, Sn, Sb, Te, and Hg in high-purity gallium, arsenic, and gallium arsenide. Detection limits ranged from 50 ng/g for iron to 0.001 ng/g for scandium. Problems of contamination control, blank level, and standardization are discussed.
Authors:K. Bachari, R. M. Guerroudj, and M. Lamouchi
study, we report the synthesis and characterization of gallium-modified folded sheet mesoporous materials synthesized by a M-H process with different Si/Ga ratios (Si/Fe = 80, 50, 20) and their test as catalysts for the tert -butylation of phenol
Authors:Laure-Marie Grand, Sara Palmer, and Ray Frost
Hydrotalcites based upon gallium as a replacement for aluminium in hydrotalcite over a Mg/Al ratio of 2:1 to 4:1 were synthesised.
The d(003) spacing varied from 7.83 Å for the 2:1 hydrotalcite to 8.15 Å for the 3:1 gallium containing hydrotalcite. A comparison
is made with the Mg/Al hydrotalcite in which the d(003) spacing for the Mg/Al hydrotalcite varied from 7.62 Å for the 2:1 Mg hydrotalcite to 7.98 Å for the 4:1 hydrotalcite.
The thermal stability of the gallium containing hydrotalcite was determined using thermogravimetric analysis. Four mass loss
steps at 77, 263–280, 485 and 828 °C with mass losses of 10.23, 21.55, 5.20 and 7.58% are attributed to dehydration, dehydroxylation
and decarbonation. The thermal stability of the gallium containing hydrotalcite is slightly less than the aluminium hydrotalcite.
Neutron activation is suggested for the determination of Pt, Au, Hg, Sc, Zn and Sn in high purity gallium. Pt, Hg and Au are
reduced to metals, gallium is extracted and then Sc, Zn, and Sn are separated on Dowex 1×8 ion exhanger. All components except
Sn are determined by substoichiometric methods in the form of chelate complexes. Sn is extracted with oxine into chloroform,
and the chemical yield measured by spectrophotometry.
Gallium phosphide is a new type of semi-conductor material. Although this substance becomes highly radioactive after neutron
irradiation, because of the nature of its component elements (gallium and phosphorus) the chances were that the great sensitivity
of the neutron activation technique would at least partly solve this very difficult trace analysis problem. The possibilities
of non-destructive analysis of long lived elements (Co−Sb−Sc−Zn−Fe...) were investigated first. To extend this method to the
determination of medium-life elements, different methods of radiochemical separation plan was worked out. Finally the method
developed gives quantitative analysis of fourteen elements (Ag−As−Au−Ba−Co−Cr−Cu−Fe−Ir−Na−Rb−Sb−Sc−Zn) amounting very often
less than one ppb.
Authors:T. Paradellis, G. Vourvopoulos, and E. Paleodimopoulos
67Ga is produced by the66Zn(d,n) reaction at 9 MeV bombarding energy. Deuterons of about 30 A obtained from the T-11 Tandem accelerator are used to bombard targets of natural Zinc prepared by electroplating onto thick copper disks. Radiochemical separation of gallium is performed by using a cation exchange column. The optimum conditions for an efficient separation are given in detail.
A method for the purification of technical grade gallium from bismuth and polonium by melting under synthetic slags is proposed. The examination of the purification degrees of gallium from bismuth and polonium was carried out with the aid of radioactive tracers210Bi and210Po. In order to obtain a gallium-bismuth alloy a suitable apparatus was assembled. The conditions of melting were established. The optimum conditions for the purification of gallium were established and the purification degrees of gallium from bismuth and polonium were determined.
Authors:K. Shikano, H. Yonezawa, and T. Shigematsu
Ultra trace carbon in gallium arsenide has been determined by deuteron activation analysis. It consists of steam distillation of nitrogen as ammonia and successive substoichiometric precipitation as ammonium tetraphenylborate. It is confirmed that nitrogen is precipitated substoichiometrically as ammonium tetraphenylborate in spite of the various chemical species of13N. The procedure developed was applied to the deuteron activation analysis of carbon in carbon-doped and undoped gallium arsenides. It took 30 minutes from the end of irradiation to the start of the radioactivity measurement. The detection limit of carbon in gallium arsenide was as low as 1 ppb.