[en] For several years Mound has actively contributed to the development of the measurement of plutonium isotopic composition by gamma-ray spectrometry. This development effort has been conducted primarily in support of calorimetry and safeguards measurements. As part of this effort, Mound has participated in a number of sample exchange programs. For the Metals Exchange Program, Mound has reported the results of isotopic measurements obtained by nondestructive (gamma-ray spectrometry) and destructive (mass spectrometry and alpha counting) means. Comparisons of the recent performance of nondestructive and destructive isotopics measurements at Mound will be presented. In addition, the instrumentation required for data acquisition and analysis of gamma-ray spectrometry measurements and their benefits will be presented. (author)

[en] The analytical chemistry laboratory of GSF is concerned with trace element analysis mainly in connection with life sciences. It analyses annually 20,000 samples with an average of 20 elements per sample. Several different analytical techniques, including neutron activation analysis and non-nuclear methods are available. The paper discusses the advantages and disadvantages of the different analytical techniques as applied to biological and environmental samples. (author)

[en] Since the first nuclear research reactor and accelerator was built in 1958 activation analysis methods have been developed and applied in China. Four national activation analysis symposiums have been held. More than 200 papers on activation analysis have been published. The paper gives a review of applications. A miniature research reactor, MNSR, designed for neutron activation analysis is described. (author). 7 refs

[en] This paper discusses applications of the radiotracers to methodological studies in trace element analysis. Owing to some unique features, the radiotracer technique has proved to be an indispensable means for examining the individual steps of an analytical procedure and revealing the concomitant sources of systematic error. In most cases, the radiotracer technique is the optimum approach, and some problems cannot be solved by other means. The examples discussed in more detail were taken from the analytical chemistry of mercury, sulphur, lead and selenium. The radiotracer investigations aimed at improving the accuracy of analytical procedures. (author). 16 refs, 6 figs, 1 tab

[en] Speciative determination of phosphorus (PO₄^3-, PO₃^3- and total P) in natural water samples can be achieved by using the reverse isotope exchange method. Five ml of a natural water sample is taken and dil. H₂SO₄ solution of ammonium molybdophosphate and a definite activity (a₀) of ³²P (in PO₄^3- form) are added. The solution is shaken with the 1,2-dichloroethane solution of tetraphenylarsonium molybdophosphate which contains a definite amount of P (W₁). After the quickly attainable exchange equilibrium between phosphate in the aqueous phase and tetraphenylarsonium molybdophosphate in the organic phase, the activity of the organic phase (a₂) is measured. The amounts of P (W_x) in the sample can be obtained by the equation of W_x=(a₀/a₂-1)W₁. In this condition, only PO₄^3- exchanges, while PO₃^3- does not. Therefore, PO₄^3- can be determined in the presence of PO₃^3- and unexchangeable phosphorus. When the sample water is treated with Br₂ water in advance, the amount of PO₄^3- + PO₃^3- can be obtained. When the sample is treated with H₂SO₄ and HNO₃, then the amount of total P can be obtained. The method is compared with the conventional spectrophotometric method (the molybdenum-blue method). This method is much simpler and more rapid, and moreover, the speciative determination is possible. (author). 13 refs, 2 figs, 6 tabs

[en] At the Reactor Laboratory neutron activation analysis (NAA) of geological samples is performed on an analytical service basis. The expenses of this activity is expected to be covered by the income. Methods and automatic analyzers have been developed for the low cost analysis of large numbers of samples. During the period 1973-79, 20,000-30,000 uranium determinations were made annually. During the period 1982-85 more than 10,000 samples were analyzed annually for gold and 23 other elements. The performance and cost of NAA compared with competitive methods are discussed. (author). 5 refs, 2 figs, 3 tabs

[en] Abstract only

[en] Nuclear methods of chemical analysis have played a prominent role in the accurate determination of the composition of Standard Reference Materials and other standards. The characteristic sensitivity, multielement capability, and freedom from chemical biases unique to nuclear methods assure them a continuing role in the standards laboratory. (author). 31 refs

[en] The instrumental neutron activation analytical technique (INAA) both competes with and complements conventional commercial analytical methods like X-ray fluorescence emission spectrometry (XRF), direct coupled plasma emission spectrometry (DCP), inductively coupled plasma emission spectrometry (ICP), inductively coupled plasma-mass spectrometry (ICP-MS) and atomic absorption (A.A.). The major advantages to the use of INAA in the geological field includes the fact that the analysis can be done non-destructively without encountering the many problems inherent in acid dissolution or fire assay techniques. The sensitivity for many elements are still unrivalled by commercially available analytical techniques for gold, platinum-group-elements, many of the rare earth elements and other elements. The multi-element nature of the analysis combined with ease of automation, data collection and spectral analysis procedures allows for rapid turnaround of samples at low cost. This technique competes very favourably with virtually all other analytical techniques. The geological market being served by INAA includes university and government researchers as well as the mineral exploration industry. The needs of these groups varies considerably and will be discussed. The various applications of INAA to the geological community will also be discussed. (author). 6 refs, 5 tabs

[en] Immunoassay is a very specific, sensitive, and widely applicable analytical technique. Recent advances in genetic engineering have led to the development of monoclonal antibodies which further improves the specificity of immunoassays. Originally, radioisotopes were used to label the antigens and antibodies used in immunoassays. However, in the last decade, numerous types of immunoassays have been developed which utilize enzymes and fluorescent dyes as labels. Given the technical, safety, health, and disposal problems associated with using radioisotopes, immunoassays that utilize the enzyme and fluorescent labels are rapidly replacing those using radioisotope labels. These newer techniques are as sensitive, are easily automated, have stable reagents, and do not have a disposal problem. (author). 6 refs, 1 fig., 2 tabs