The growing awareness of the environmental impact of beef production is greatly influencing the consumption decision.Beef production is strongly criticized due to the remarkable environmental impact of this activity, associated with problems of deforestation, water consumption, global warming, and climate change.Despite this, livestock food products play an important role in food security, accounting for 33% of global protein consumption.Enhancing the transparency of the beef production chain is essential to increase consumer perception about its origin, safety for consumption, environmental and human aspects.A study was undertaken to assess if beef samples from different producing countries can be distinguished from another on basis of their contents of chemical elements.Beef samples from some of the top world exporters, Brazil (1 st ), Australia (2 nd ), Argentina (5 th ), Uruguay (8 th ), and Paraguay (9 th ), were analyzed by neutron activation analysis for multi-element determination.Five machine learning algorithms, Classification and Regression Tree (CART), Multilayer Perceptron (MLP), Naive Bayes (NB), Random Forest (RF), and Sequential Minimal Optimization (SMO), were used to analyze the measurement results and classify the beef producing countries.MLP model provided the best classification performance, with an accuracy of 100%, 98%, 98%, 96%, and 82% respectively for Paraguay, Uruguay, Australia, Argentina, and Brazil.Reducing the number of classes (each country against the remaining countries), the accuracy achieved for the Brazilian beef samples was improved to 94% without changing the performance for other countries.Multi-element compositional data and machine learning algorithms allowed for discriminating beef producing countries, providing an outlook of becoming a valuable tool for geographical origin traceability and transparency.

Sample-size reduction including homogenization is often required to obtain a test portion for element compositional analysis. Analyses of replicate test portions may provide insight into the sampling constant, and often much larger quantities are needed to limit the contribution of sampling error. In addition, it cannot be demonstrated that the finally obtained test portion is truly representative of the originally collected material. Nuclear analytical techniques such as neutron and photon activation analysis and (neutron-induced) prompt gamma activation analyses can now be used to study and overcome these analytical problems. These techniques are capable of obtaining multi-element measurements from irregularly shaped objects with masses ranging from multiple grams to multiple kilograms. Prompt gamma analysis can be combined with neutron tomography, resulting in position-sensitive information. The analysis of large samples provides unprecedented complementary opportunities for the mineral and geosciences. It enables the experimental assessment of the representativeness of test portions of the originally collected material, as well as the analysis of samples that are not allowed to be sub-sampled or dissolved, the analysis of materials that are difficult to be homogenized at large, and studies on the location of inhomogeneities. Examples of such applications of large-sample analyses are described herein.

The International Atomic Energy Agency (IAEA) has implemented a detailed E-learning on-line course in neutron activation analysis (NAA). Existing books and guidance documents on the concepts and execution of NAA are out of date and not sufficient anymore to ensure the transfer of current knowledge on its practice. The overall objective of the E-learning tool in NAA is to realize a 'living book', summarizing the basic concepts and providing practical information on the implementation of the methodologies which can be more easily updated than a common book, allowing also for visualization using contemporary media.

These recommendations are a vocabulary of basic radioanalytical terms which are relevant to radioanalysis, nuclear analysis and related techniques. Radioanalytical methods consider all nuclear-related techniques for the characterization of materials where 'characterization' refers to compositional (in terms of the identity and quantity of specified elements, nuclides, and their chemical species) and structural (in terms of location, dislocation, etc. of specified elements, nuclides, and their species) analyses, involving nuclear processes (nuclear reactions, nuclear radiations, etc.), nuclear techniques (reactors, accelerators, radiation detectors, etc.), and nuclear effects (hyperfine interactions, etc.). In the present compilation, basic radioanalytical terms are included which are relevant to radioanalysis, nuclear analysis and related techniques.

As a safer alternative for the use of radioactive tracers, the enriched stable 58Fe isotope has been introduced in studies of iron metabolism. In this study this isotope is measured with instrumental neutron activation analysis (INAA) in blood samples of patients with iron related disorders and controls after oral ingestion of a 58Fe containing pharmaceutical. Results were compared with those derived from MC-ICP-MS, applied on the same samples, and analytical and practical aspects of the two techniques were compared. Both techniques showed an increased absorption and incorporation in red blood cells of the 58Fe isotope in iron deficient patients in contrast to the controls. In all individuals results of INAA measurements were in good agreement with those of MC-ICP-MS (|zeta| < 2). Uncertainties in INAA are substantially higher than those achievable by MC-ICP-MS but the INAA technique offers a high specificity and selectivity for iron close to 100%. In contrast to INAA, sample preparation before measurement is very critical in MC-ICP-MS and interferences with 58Ni and 54Cr may hamper the measurement of 58Fe and 54Fe respectively. Since it takes at least five days after irradiation to reduce the activity of interfering radionuclides (mainly 24Na), INAA is a more time consuming procedure; the need of a nuclear reactor facility makes it also less accessible than MC-ICP-MS. Costs are comparable. Both INAA and MC-ICP-MS are able to adequately measure changes in iron isotope composition in blood when an enriched stable iron isotope is applied in clinical research. Although MC-ICP-MS is more sensitive, is faster and has easier access, in INAA preparative steps before measurement are simpler and there are hardly demands on the kind and size of the samples. This may be relevant working with biomaterials in a clinical setting.

The neutron irradiation of molybdenum hexacarbonyl has been systematically studied to identify possible improvements for the production of molybdenum-99. After irradiation, the targets were dissolved in dichloromethane, and Szilard-Chalmers liquid-liquid extraction was carried out with aqueous extractants. The effects of the irradiation time, the aqueous phase composition and the irradiated mass were studied with a focus on the chemistry involved. Stable extraction yields of 20% were obtained with enrichment decreasing with target decomposition. Improved enrichment requires decreased decomposition.

Brazilian and Chinese eye shadow powders were evaluated for assessing the cosmetics as a source of contamination during sample preparation of biological materials. Nineteen chemical elements were measured by INAA. Highest mass fractions measured were for Ba (~ 2.5%), Cr (~ 1%), Fe (~ 45%), Na (~ 10%) and Sn (~ 1). It was experimentally verified that more than 0.01 mg of eye shadow may drop off and as such may be a potential source of contamination, causing high relative errors depending on the type of biological matrices and chemical element considered.

The quality of dog diets depends on adequate ingredients capable of providing optimal nutrition and free of contaminants, for promoting long-term health. Trace elements in 95 samples of dry food for dog puppies (n = 32) and adults (n = 63) of various brands were measured using instrumental neutron activation analysis (INAA). The mass fractions of most elements were within the permissible limits for dogs. Aluminum, antimony, and uranium presented fairly high levels in some samples, which may imply health risks. Aluminum mass fractions ranged from <21 to 11,900 mg/kg, in same brand, super-premium dog food. Antimony mass fractions ranged up to 5.14 mg/kg, with the highest values measured in six samples of dog food from the same producer. The mass fractions of uranium was found up to 4 mg/kg in commercial brands from five different producers.

A crucial part of any chemical analysis is the degree of representativeness of the measurand(s) in the test portion for the same measurands in the object, originally collected for investigation. Such an object usually may have either to be homogenized and sub-sampled, or digested/dissolved. Any of these steps introduce sampling errors, risk of contamination or loss of the measurand(s). Neutron (and photon) activation analysis and prompt gamma analysis have the capabilities of analyzing large objects or samples without the need of any pre-treatment, i.e., intact ‘as received’, with masses varying from tens of grams to tens of kilograms, and with any type of (irregular) shape. The basic concept of neutron activation analysis and prompt gamma analysis are shortly revisited and the scope of application of the large sample analysis with these technique are elaborated on with an outlook for use in forensic studies, including the analysis of medicinal products and drugs of abuse.

This study examines the potential to use instrumental neutron activation analysis (INAA) to explore temporal and geographical variation in exposure to heavy metals and other selected elements in common kestrel Falco tinnunculus using feathers from a natural history collection. The study gathered samples of two breast feathers from each of 16 adult male kestrel specimens from Naturalis Biodiversity Centre, collected in The Netherlands between 1901 and 2001. Feather samples were analysed for more than 50 elements, using INAA at the Reactor Institute Delft. Results (in mg/kg dw) were transformed into ratios of milligram of element per millimetre of feather length. The distribution of the mass fractions and ratios was plotted for each element against time and by geographical area. Observed mass fractions and/or ratios are discussed for selected elements (Hg, Cd, Zn, Pt, Pd, Se, Al, Rb, As, Sb, Cr, V, Cl, Br) known to have, at certain concentrations, adverse effects on raptors. Some samples show mass fractions of certain elements (Cr, Cd, Se, As) above levels known to have adverse effects. We conclude that the analysis of museum feathers using INAA provides reference values for concentrations of selected elements, including those of high societal concern such as Hg and Cd, against which to assess concentrations of these elements in feathers of present-day living raptor populations.

Three multi-element techniques employed for analysis of lichen transplants deployed at sites in Romania with strongly differing exposure to air pollutants were compared with respect to precision and determination limits for 54 elements. The results obtained for Evernia prunastri (unexposed and 6 months' exposure at three sites) are presented here. The techniques were energy dispersive X-ray fluorescence analysis (EDXRF), sector-field inductively-coupled plasma mass spectrometry (ICPMS), and instrumental neutron activation analysis (INAA). From an assessment of the data the EDXRF values were preferred for 3 elements (Ni, Cu, Pb), ICPMS for 18 elements (B, Mg, P, Ga, Rb, Sr, Y, Mo, Ag, Cd, In, Sn, Cs, Ba, Pr, Hg, T1, Bi), and INAA for 23 elements (Na, Al, Cl, Ti, Cr, Co, Se, Br, I, La, Ce, Sm, Eu, Tb, Dy, Yb, Lu, Hf, Ta, W, Au, Th, U). For the remaining 10 elements (S, K, Ca, Sc, V, Mn, Fe, Zn, As, Sb) two or all three techniques gave results of similar quality. In spite of good performance relative to certified reference materials the ICPMS data for some elements were systematic low relative to corresponding data from INAA and EDXRF, presumably because the samples contained mineral matter not dissolved in the nitric acid dissolution for ICPMS.

The 14th International Conference on Modern Trends in Activation Analysis, MTAA14, and the 11th International Conference on Nuclear Analytical Methods in the Life Science, NAMLS11, were held consecutively from August 23 2015, in Delft, The Netherlands, at the premises of the Delft University of Technology. MTAA14 was chaired by Peter Bode; NAMLS11 was chaired by Antonia Denkova, both from the Delft University of Technology. Professor Marcel de Bruin (same university) was honorary chair of MTAA14.

Dog food from 24 regular 1 kg bags of the same production lot was evaluated by LS-NAA and conventional NAA. After analyzing the entire content of bags by LS-NAA, one test portion of 350 mg from each bag was evaluated by NAA. Br, Ca, K, Na and Zn could be measured by LS NAA and, except for K, the variability was higher than the uncertainty of measurement, indicating differences of composition between bags. The variation of results obtained from conventional NAA agreed with that from LS-NAA, confirming the representativeness of the small portions.

The aim of this study was to assess the accuracy of the results of whole-body measurements by comparison with the urine collection method in the PRRT with (177)Lu and furthermore to develop a more accurate method of paired measurements. Excreted samples were collected at given intervals and activities were measured by a dose calibrator. Traditionally, whole-body activities during subsequent measurements are normalized individually to the administered activity. In order to correct for the effects of the activity in the bladder during the baseline measurement before the first voiding and activity redistributions in the patient body during subsequent measurements, a series of paired measurements before and after each voiding were carried out. Time-dependent detector responses at given times were derived and time-activity retentions were then determined. Compared to the results of the urine collection, whole-body activities by traditional whole-body measurements were overestimated by ca. 14% at 1 h after administration and randomly varied from -29% to 49% at 24 h. Measurement uncertainties of whole-body activities were from ± 4% (the coverage factor k=2) at 1 h to >± 20% at 24 h by the urine collection and ± 7% by paired measurements, respectively. Whole-body activities at 1 h by paired measurements were validated using the results by measurements of the collected first urine. The new method of paired measurements has an equivalent measurement accuracy and even better during the later measurements with respect to the urine collection method and therefore can replace urine approach for assessing the time-activity remaining in the patient body.

Instrumental and radiochemical neutron activation analysis (INAA and RNAA, respectively) in combination with inductively coupled plasma mass spectrometry were used for the measurement of 52 constituent elements in 120 h Xenopus laevis larvae. With this approach macro and trace elements were measured in X. laevis larvae samples. The validation of the analytical techniques was performed by using certified reference materials and by recovery tests. Our feasibility study appears relevant for future studies on the bioaccumulation patterns of elements in Xenopus as effective indicators of environmental metal contamination.

Neutron activation laboratories worldwide are at a turning point at which new staff has to be found for the retiring pioneers from the 1960s–1970s. A scientific career in a well-understood technique, often characterized as ‘mature’ may only be attractive to young scientists if still challenges for further improvement and inspiring new applications can be offered. The strengths and weaknesses of neutron activation analysis (NAA) are revisited to identify opportunities for innovation. Position-sensitive detection of elements in large samples, Monte Carlo calculations replacing the use of standards, use of scintillator detectors and new deconvolution techniques for increasing the sensitivity are examples of challenging new roads in NAA. Material science provides challenges for the application of NAA in both bulk samples, ultrathin layers and ultrapure materials.

The laboratory for instrumental neutron activation analysis at the Reactor Institute Delft, Delft University of Technology uses a network of 3 gamma-ray spectrometers with well-type detectors and 2 gamma-ray spectrometers with coaxial detectors, all equipped with modern sample changers, as well as 2 spectrometers with coaxial detectors at the two fast rabbit systems. A wide variety of samples is processed through the system, all at specific optimized (and thus different) analytical protocols, and using different combination of the spectrometer systems. The gamma-ray spectra are analyzed by several qualified operators. The laboratory therefore needs to anticipate on the occurrence of random and systematic inconsistencies in the results (such as bias, non-linearity or wrong assignments due to spectral interferences) resulting from differences in operator performance, selection of analytical protocol and experimental conditions. This has been accomplished by taking advantage of the systematic processing of internal quality control samples such as certified reference materials and blanks in each test run. The data from these internal quality control analyses have been stored in a databank since 1991, and are now used to assess the various method performance indicators as indicators for the method’s robustness.

The development on neutron activation analysis (NAA) into a technique of practical interest effectively started about 60 years ago, when nuclear reactors became available and widely accessible as intense sources of neutrons. During 50 out these 60 years, the series of Modern Trends in Activation Analysis (MTAA) Conferences acted as a true companion and facilitator of this growth. As trendwatcher they signalized the many initiatives that contributed to the development of activation analysis and its applications. A period has come to an end of impressive development resulting from sometimes revolutionary changes in radiation detection and data processing, and much improved irradiation facilities, NAA has reached a full stage of development, with emphasis on routine application and with remaining developments of in marginal impact. NAA is being challenged increasingly in the last 30 years by alternative techniques for multi trace element analysis. The MTAA Conference and with it the ICAA, the International Committee on Activation Analysis, can play an important and active role in this process of identifying and selecting key areas, and even promoting concerted action in those areas. Such an evolution of focus from retrospective to prospective, from trendwatcher to trendsetter, may well allow the MTAA Conference to continue and even expand its role in future development of NAA and its applications. The ideas about the future of the MTAA Conferences and its organization are elaborated upon and some possible subjects for focused development activities are indicated.

For the identification of human exposure to one of the most toxic compounds, which is methyl mercury (MeHg(+)), fingernail clippings were selected as the matrix of interest. Within this pilot study, six samples from different origins and from people with different food consumption patterns were chosen. Species-analysis of MeHg(+) was performed according to the following procedure: dissolution of the sample material in tetramethylammonium hydroxide (TMAH), derivatisation of MeHg(+) with sodium tetraethylborate (NaBEt(4)), extraction into iso-octane and measurement with gas chromatography hyphenated to inductively coupled plasma mass spectrometry (GC-ICPMS) for the quantification MeHg(+).