Role Of Neutron Activation Analysis Research Articles

The role of NAA in securing the accuracy of analytical results in the inorganic trace analysis

The unique value of the neutron activation analysis (NAA) for analytical quality assurance is demonstrated through its contribution to the certification of the reference materials over the time span of 40 years. Ratio primary reference measurement procedures i.e. definitive methods, based on radiochemical NAA, play an important role in confirming the validity of the certified values established in the international intercomparisons. Real analytical situations where the use of NAA was critical to get accurate results are presented. The dangers associated with the possible non-availability of the NAA in the near future are indicated.

50 Years of adventures with neutron activation analysis with the special emphasis on radiochemical separations

Author’s activity in the field of neutron activation analysis (NAA) over the past 50 years is reviewed and the changing role of radiochemical separations in NAA is discussed. Two philosophies which have existed in this area are reminded and their evolution in time is described. New ion exchange systems for the separation of trace elements were devised and the role of NAA in certification of reference materials is highlighted. The idea of definitive methods by RNAA (now named: ratio primary reference measurement procedures, RPRMPs) is presented and illustrated by several examples. The role of RPRMPs in quality assurance in inorganic trace analysis is emphasized.

Methodological developments and applications of neutron activation analysis

The paper reviews the author’s experience acquired and achievements made in methodological developments of neutron activation analysis (NAA) of mostly biological materials. These involve epithermal neutron activation analysis, radiochemical neutron activation analysis using both single-and multi-element separation procedures, use of various counting modes, and the development and use of self-verification principle. The role of NAA in the detection of analytical errors is discussed and examples of applications of the procedures developed are given.

Metrological role of neutron activation analysis. III. Role of INAA in sampling behavior characterization

The minimum sample size, usually 100 mg or larger, is often the only information given on certificates of existing certified reference materials (CRMs) to describe sampling behavior. This value is not only too large for quality control requirements of microanalysis, but also too general to reflect the strong element-specific nature of the sampling behavior of solid materials. In this paper, the third and final of the series, we explain the need for CRMs with sampling behavior characterized for individual elements and describe the unique role of instrumental neutron activation analysis in sampling behaviour characterization.

Metrological role of neutron activation analysis. II. Parametric INAA – an ideal back-up for INAA as a primary ratio method of measurement

In this paper, the second of this series, traceability and uncertainty of measurement results by k0-INAA will be described. The role of k0-INAA as a back-up to relative INAA will be discussed.

Metrological role of neutron activation analysis. IB. Inherent characteristics of relative INAA as a primary ratio method of measurement

This is the second part of a paper which deals with the advantages and disadvantages of relative instrumental neutron activation analysis concerning traceability and uncertainty, and the current scope and possible future extensions of neutron activation analysis as a primary ratio method. The first part of this paper has been published in this Journal [1].

Metrological role of neutron activation analysis. IA. Inherent characteristics of relative INAA as a primary ratio method of measurement

Metrological role of neutron activation analysis. IA. Inherent characteristics of relative INAA as a primary ratio method of measurement

The Role of Neutron Activation Analysis at The Dow Chemical Company

The role of neutron activation analysis (NAA) at The Dow Chemical Company has not changed significantly since the first operations, which were conducted in July, 1967. That role is threefold; provide results with appropriate precision, accuracy and sensitivity; provide results in a timely manner; and provide results for a reasonable cost. What has changed, are the requirements for satisfying each of the three components of the role. In a business-focused environment, analyses need to be performed faster with better sensitivity and/or precision and be more cost efficient. In order to meet these requirements, operations at The Dow TRIGA Research Reactor are devoted to NAA activities.

Current Role of NAA in Biological and Health-Related Environmental Studies as Exemplified by Programs of the IAEA

The International Atomic Energy Agency (IAEA) has many projects and activities supporting the utilization of nuclear research reactors for neutron activation analysis (NAA). Globally the number of operating nuclear research reactors has been in decline since about 1975. This contrasts with the situation in developing countries where the numbers show a modest increase over the same period. This paper reviews the current status of NAA as seen from the particular perspective of IAEA programs involving studies of biological and environmental specimens. Some of the areas in which NAA is maintaining its role as a competitive technique are briefly reviewed.

Trends in trace element determinations in blood, serum, and urine of the Dutch population, and the role of neutron activation analysis.

A critical review on the quality of literature data on trace elements in human blood, serum, and urine of inhabitants in the Netherlands has shown that many of the currently available data have been established 15-20 years ago. Only in a few publications are quality indicators mentioned, which should be considered typical--and minimal--for studies resulting at reference values. The use of neutron activation analysis for determination of trace elements in human body fluids was restricted to a few studies in the 1970s. However, although it is frequently assumed that the sensitivity of NAA might be insufficient, it is demonstrated that modern, large, well-type Ge detectors may serve well for the determination of trace elements in human body fluids via radiochemical NAA, for example.

Role of NAA in the characterization of sampling behaviors of multiple elements in CRMs

Taking the advantage of the high precision and accuracy of neutron activation analysis (NAA), sampling constants have been determined for multielements in several international and Chinese reference materials. The suggested technique may be used for finding elements in existing CRMs qualified for quality control (QC) of small size samples (several mg or less), and characterizing sampling behaviors of multielements in new CRMs specifically made for QC of microanalysis.

From misconception to a must: The measured merits of total quality management and accreditation in INAA

Increasingly govemmental bodies and industry require that supporting analytical laboratories have their quality assurance program implemented in a quality system by international standards such as derived from the ISO-25 guide. Neutron activation analysis (NAA) laboratories may have to deal with this trend too. In universities and research laboratories the need for it, and the implications of total quality management system are sometimes misconceived by unfamiliarity with the issue. The laboratory for INAA in Delft has been accredited for its quality system since 1993. Some of the tangible improvements since the introduction of quality management are presented. Four strategical considerations are given to consider the introduction of quality management at NAA laboratories, viz. with respect to the role of NAA for the validation of other methods, the role of NAA in the certification of reference materials, the preservation of knowledge and the acceptance of NAA as a respectable method.

95/06575 Ombrotrophic peat bogs as monitors of trends in atmospheric deposition of pollutants: Role of neutron activation analysis in studies of peat samples

95/06575 Ombrotrophic peat bogs as monitors of trends in atmospheric deposition of pollutants: Role of neutron activation analysis in studies of peat samples

Ombrotrophic peat bogs as monitors of trends in atmospheric deposition of pollutants: Role of neutron activation analysis in studies of peat samples

Ombrotrophic peat bogs, which are quite common in temperate regions, receive chemical compounds only from the atmosphere. These bogs are therefore well suited to study temporal and spatial trends of air pollutants such as heavy metals, provided that the substances concerned are sufficiently strongly retained in the peat. In this paper, the use of instrumental and radiochemical neutron activation analysis to study trace elements in ombrotrophic peat is described. This work has provided very useful information with respect to the impact of long range atmospheric transport of pollutants to different parts of Norway, and has also been shown to be a useful tool in the study of natural trace element cycling processes. Elements discussed in particular are Zn, Se, Sb, and Br.

The contribution of various analytical techniques to the certification of reference materials

Two international intercomparisons on the determination of trace elements in geological-environmental materials as well as two similar intercomparisons with biological materials provided a large amount of data elucidating the relative significance of various analytical techniques in the process of certification. The data have been investigated concerning their frequency of use, agreement of results by various techniques, percentage of outliers and general performance of the methods. Because many laboratories supplied results for both biological materials and both materials of mineral origin, the analysis of data in the form of two-sample charts has also been presented. The significance of an adequate procedure for outlier rejection for the proper assigning of certified values is emphasized and the unique role of neutron activation analysis in the certification process has been demonstrated. The use of highly reliable (“definitive”) methods for the verification of recommended values has been demonstrated.

On the role of neutron activation analysis in the certification of a new reference material for trace-element studies, mixed human diet, H-9

A new biological reference material, which is representative of diets consumed in Finland, has been characterized by means of an intercomparison exercise conducted by the IAEA in the second half of 1985 and in 1986. Results for 35 elements received from 79 participants in 33 countries have been evaluated. A certificate of analysis has been issued with provisional certified values for 22 elements and information values for 2 elements. Neutron activation analysis (NAA) provided approximately one third of all the results reported. Instrumental NAA was used approximately 5 times as frequently as radiochemical NAA. Overall, NAA played an important role in providing useful data for the following 20 elements: Al, As, Br, Cl, Co, Cr, Cs, F, Fe, Hg, I, K, Mn, Mo, Na, Rb, Sb, Sc, Se and Zn. In comparison with the main competing non-nuclear method (usually atomic absorption spectrometry), NAA showed a larger dispersion of results for Cd, Cu, K, and Mg, and a smaller degree of dispersion for Co, Cr, Hg, and Se.

The role of neutron activation analysis in the certification of NBS Standard Reference Materials

Neutron activation analysis (NAA) is used extensively at the National Bureau of Standards as one of the analytical techniques in the certification of Standard Reference Materials (SRMs). Characteristics of NAA which make it valuable in this role are: accuracy; multielemental capability; ability to assess homogeneity; high sensitivity for many elements, and essentially blank-free nature. Examples of recent SRM analyses illustrating these characteristics are described.

The role of neutron activation analysis and radioanalytical methods in dose-effect relationship studies for the setting of trace metal protection criteria

In order to prepare scientifically accurate health protection criteria documents for trace metals integrated multidisciplinary research is necessary. In particular, the rational for structuring the documents should be based primarily on the two major questions of exposure and response. Unfortunately, in a majority of cases there is a paucity of relevant data to the establishment of dose-effect relationships. This work intends to show the role that neutron activation analysis and radiotracers with very high specific radioactivity have in solving problems relevant for establishing dose-effect relationships for trace metals. Typical applications in the different research areas involved in the preparation of the protection criteria, from source and exposure to levels and forms of trace metals in humans, are presented.

The role of neutron activation analysis in VLSI manufacturing and development

Very large scale integrated (VLSI) semiconductor manufacturing and development require trace analyses for materials inspections, process characterization, contamination control, and failure analysis. Improvement in alternate analytical techniques has reduced the relative importance of neutron activation analysis (NAA) in these activities, but, for certain types of problems, NAA can still play a significant role.

Role of neutron activation analysis in the evaluation of sampling, storage, and analysis of samples for the national environmental banking system

Some problems inherent to the sampling, storage and analysis of whole organs or tissue biopsies were studied. The method used to evaluate the proper conditions of these, was neutron activation analysis.