Authors:Tian Weizhi, Ni Bangfa, Wang Pingsheng, and Nie Huiling
Certifications of trace elements in existing CRMs, especially biological CRMs, are far from satisfactory. Neutron activation analysis (NAA) for its inherent advantages combined with newly established parametric standardization, may contribute to improve this situation. The continuing progress of the hybrid extended k0-relative NAA technique developed in our laboratory is discussed. Examples are given to show the reliability of the method in certification of multielements. RNAA is still one of the best methods, or even the method of choice, in analysis at sub-g/g concentration levels. The suitability of the technique for this purpose has been studied through the determination of rare earth elements at ng/g concentration level in two Chinese biological CRMs using both RNAA and ICPMS. Sampling behaviors of multielements in CRMs have been studied by INAA in an effort to develop CRMs suitable for analysis with small sample sizes.
Authors:S. Landsberger, D. Wu, S. Vermette, and W. Cizek
Fifty air filters with fine and coarse fractions were prepared from NIST 2710 contaminated soil. Eighteen pairs were made and sent to laboratories of the Coordinated Research Program (CRP) on Applied Research on Air Pollution Using Nuclear-Related Analytical Techniques for elemental determination. The results of this intercomparison are discussed in this paper.
Deux nouveaux milieux biologiques SRM-1571 (Feuilles végétales) et SRM-1577 (Foie de boeuf), viennent d'être distribués par
le NBS comme échantillon de référence (SRM). La concentration d'un certain nombre d'éléments à l'état de trace a été certifiée
dans ces milieux. On décrit la préparation et le programme analytique de ces étalons; le grand intérêt de tels milieux serait
d'assurer un contrôle de qualité et de permettre le développement de nouveaux procédés pour l'analyse des milieux biologiques.
Instrumental neutron activation analysis of eight geochemical standard materials has been carried-out and the concentration values of nine rare-earth elements (REE) (La, Ce, Nd, Sm, Eu, Gd, Tb, Yb and Lu) have been determined. Discussion of some problems in the determination of those elements is presented and the results obtained are compared with literature values. In general, good agreement with available data was obtained but discrepancies with concentration values for a number of elements in some of these standards are discussed.
Chromium is recognized to be an essential trace element in several biological systems. It exists in many biological materials
in a variety of chemical forms and very low concentration levels which cause problems for many analytical techniques. Both
instrumental and destructive neutron activation analysis were used to determine the chromium concentration in Orchard Leaves,
SRM 1571, Brewers Yeast, SRM 1569, and Bovine Liver, SRM 1577. Some of the problems inherent with determining chromium in
certain biological matrices and the data obtained here at the National Bureau of Standards using this technique are dicussed.
Trace element analysis has been carried out on standard biological reference samples such as bovine liver, orchard and tomato
leaves. Computer aided instrumental neutron activation analysis and, in some cases, preliminary chemical group separation
followed by NAA were used. For Ca, Mg, Ni and Si special chemical separation and Cerenkov counting were applied. *** DIRECT
SUPPORT *** A1353068 00003
Authors:H. Nakahara, M. Tsukada, A. Moriizumi, K. Horiuchi, and Y. Murakami
The improvement obtained by epithermal neutron activation analysis was studied in terms of the detection sensitivity and precision
in the γ-ray spectrometry for geological and biological reference samples. For geological samples, small improvement was observed
only for the elements As, Ba, Sb, Se and U. For biological samples, however, large improvement was observed for As, Br, Sb
and U. The ratio of the resonance integral to the effective thermal-neutron capture cross section was observed for 19 nuclides.
The effect of the (n, p) reaction to the determination of Al and Mg by the ordinary reaktor-neutron activation analysis was
A method of rapid determination for indium, nickel and copper in Spinach (NBS; SRM-1570) by substoichiometric radioactivation
analysis is described. The method is based on the principle that an equal amount of non-irradiated test sample is added to
the irradiated standard sample and subsequent substoichiometric extraction for the irradiated test and standard samples is
carried out. Indium is extracted as diethyldithiocarbamate into carbon tetrachloride, nickel as dimethylglyoximate into chloroform
and copper as dithizonate into carbon tetrachloride. The radioactivities of these extracts are measured by NaI(Tl) or Ge(Li)
detector coupled with pulse-height analyser. The analytical results obtained by the method were in good agreement with our
published values and certified values by NBS.
Authors:J. Brushwood, P. Beeley, K. Neilsen, and L. Bennett
It has been demonstrated that the Shape Independent Model for k0 based INAA can be applied in the Slowpoke-2 beryllium moderated reactor. The elemental concentration determined using this methodology agreed well with both certified values and those determined by the more conventional 'B'-value method. However, the facility characterising parameter B(x,46Sc,124Sb) differed significantly from that determined in other reactor types.