Atmospheric particulate samples were collected at the geographic South pole, using cellulose and polycarbonate filters and
cascade impactors. The samples were analysed for 40 elements by instrumental neutron activation analysis. From the filter
samples atmospheric concentrations for 33 elements could be obtained. The highest atmospheric concentrations were found for
S: 49 ng/standard cubic meter (SCM) of air, Na: 3.3 ng/SCM and Cl: 2.6 ng/SCM. In the cascade impactor samples, only a few
elements were observed above blank. For these elements it could be concluded that they are associated for over 80–90% with
submicron size paricles.
Instrumental neutron activation analysis /INAA/ was applied to measure trace elements in head hair of 19 patients with impaired renal function /14 males and 5 females/ and of 40 normal individuals /20 males and 20 females/. It was the aim to use head hair as a possible indicator of total body trace elements status and to investigate whether significant changes occur as a result of chronic hemodialysis. The elemental concentrations of 20 elements /i.e. Na, Mg, Al, Cl, K, Ca, V, Mn, Fe, Co, Cu, Zn, As, Se, Br, Ag, Cd, Sb, I and Au/ are presented and compared with published data. The present study revealed that the hair of the dialysis patients contained about ten times more iodine than that of the control group. No significant differences were observed for the other elements measured, except for sodium and antimony.
Equations to calculate the second order reaction interferences in activation analysis have been derived. A simple approximation
as well as the exact solution have been investigated. A new algorithm is proposed for fast and accurate calculations, without
the need of a computer with high precision arithmetic. The method can be used for all higher order reaction chains.
Two methods are described to determine indium and managenese in high-purity tin. In the first method indium and manganese
are separated from the tin and antimony matrix activities on Dowex 1X8 anion exchanger. Tin and antimony are adsorbed in 10M HF while indium and manganese are eluted. In the second method the incident γ-ray intensity due to the tin matrix is reduced
by placing a lead absorber between the sample and the detector. The reproducibility and the sensitivity of both methods are
of the order of 10 ppb for manganese and of 1 ppb for indium for 1 g samples and a neutron flux of 1011 n·cm−2·sec−1.
The chemical composition of aerosols emitted during coal combustion was studied as a function of particle size down to 0.01 m. The aerosol collections were carried out in a 81 MW capacity boiler that burned Venezuelan coal in a circulating fluidized bed combustion chamber. The samples were analyzed with upstream of the electrostatic precipitator using a Berner low-pressure impactor, which was quipped with a cyclone pre-cutter to avoid overloading of the first impaction stages. The samples were analyzed by INAA for up to about 40 elements. The elemental concentrations in the particulate matter for each impaction stage were plotted as a function of stage number (particle size). For the elements Na, Al, K, Ca, Sc, Ti, V, Ga, La and Sm, the concentration variation was limited to a factor of 2 to 4, and the concentrations of these elements were lower for the initial and final impactor stages than for the intermediate particle sizes. The variations were also limited to a factor of 2–4 for Mn, Fe, As, Sb and Th, butall these elements showed increasing concentrations with decreasing particle size. Still other elements, such as Ni, Cr, Co, Za, W, Mo and the halogens, were highly enriched (up to 20–100 fold) in the fine particles when compared with the coarse particles.
Arsenic, selenium and antimony were determined in four different tin samples. After distillation from HBr−H2SO4 medium arsenic and selenium were precipitated with thioacetamide, and antimony was subsequently separated by deposition on
iron powder. The separated samples were counted on a high-resolution Ge(Li) γ-spectrometer. The sensitivity of the method
is highly satisfactory.
was experimentally determined for the reactions42Ca(n, p)42K,43Ca(n, p)43K and44Ca(n, p)44K. Calcium carbonate samples and fast neutron flux monitors were irradiated with and without cadmium shielding in the Thetis
reactor (Institute for Nuclear Sciences, Rijksuniversiteit, Gent). The potassium activities induced in the calcium carbonate
samples were separated and purified by tetraphenylborate precipitation, after which they were measured with a Ge(Li)-detector
of calibrated detection efficiency. On the basis of
A method was developed for the determination of 15 trace elements in tin. High-purity tin samples (99.9999% and 99.999%) as
well as tin of technical quality were analysed. Reactor neutron activation of the tin samples was followed by distillation
of the matrix activities from a HBr−H2SO4 medium and Ge(Li) gamma-ray spectrometry of the distillation residue. The sensitivity of the method is generally high. For
the high-purity samples the detection limits vary from 0.02 ppb (scandium) to 200 ppb (iron) for irradiation of 1 g of tin
for 1 week at a thermal flux of 5·1012n·cm−2. ·sec−1. To decontaminate the surface of the tin samples, pre- and post-irradiation etching procedures were applied. The efficiency
of these etching techniques was studied.
For the determination of very low concentrations of copper in tin, an analytical method involving reactor neutron activation
was developed whereby the copper activity was separated from the tin matrix by extraction of the Cu(I) cuproin complex in
n-amyl alcohol. A new decontamination technique was sought in order to remove the copper contamination present on the tin
surface. Pre-irradiation removal of the tin surface combined with post-irradiation etching appeared to be the most efficient.