Authors:J. Datta, D. Chowdhury, R. Verma, and A. Reddy
The intake of leafy vegetables in daily diet is very important to meet our nutritional needs. Vegetables provide the essential
elements which are necessary and recommended for human growth. However, due to rapid industrialization and urbanization our
environment becomes polluted and this affects the normal growth of agricultural products and composition of environmental
species. The elemental concentrations present in the environmental samples are good indicators to assess the toxicological
levels due to pollution affects. In the present work we have analysed several vegetable plant samples by instrumental neutron
activation analysis to determine the elemental concentrations at major, minor and trace levels. The leafy vegetables like
spinach, red leafy veagetable, pui, gourd leaf, lettuce and katoua were chosen as these are extensively consumed by local
peple in eastern part of India. We have determined 15 elements in the above mentioned vegetable samples and some of these
are essential elements and some are toxic elements. It was found that Na and K were present as major elements, Fe and Zn as
minor elements and As, Ce, Cr, Co, La, Mo, Rb, Sc, Sm, Sr as trace elements. The concentration level of Cr was found to be
higher than that of recommended value certified by WHO and National environment quality control for human consumption. The
validation of our analytical results have been performed by the Z-score tests through the determination of concentrations of the elements of interest in certified reference materials.
A new type of synthetic multi-element reference material (SyRM) with pseudo-biological matrix was prepared by a co-polymerization
reaction of an aqueous solution of acrylamide and acrylic acid containing known amounts of the elements. SyRM has the excellent
homogeneity and the quantitative retention of major and trace elements. Elemental composition can simulate the biological
samples to be analyzed. SyRM can be used for the same purpose of conventional certified reference materials with high accuracy
and precision. SyRM was applied as a comparative standard for non-destructive photon and α-particle activation analysis. Selective
preconcentration methods combined with NAA were proposed and the SyRM containing about fifty elements with known amounts was
prepared. In order to evaluate the reliability of present methods, 3d transition elements and rare earth elements were determined
in the SyRM. It was clearly observed that these methods have good accuracy and precision in trace analysis of biological materials
by comparing the analytical results with the original contents in the SyRM. The SyRM supported multielement analysis of marine
macro-algae can be used as comparative standards for the quality assurance of analytical techniques.
137Cs and to a lesser extent, 210Pb have been widely used for soil erosion and sedimentation studies. The accuracy of their quantification is greatly dependent on the proper handling of the sources of error that may affect the results. These include ambient background variation, attenuation for the 210Pb 45 keV gamma-photons in the sample, efficiency calibration and large statistical errors due to low levels of radioactivities and small sample quantities combined with Compton scattering of high energy photons during acquisition. In this study, we investigated the distribution of both 210Pb and 137Cs in three soil cores from Konza and Fort Riley, Kansas. Special attention was given to the analytical treatment of the spectra and the uncertainty budget. We show here that the ambient background is a major factor in the results. If it is not well monitored, errors of as high as 25& can result. We investigated the advantages of using Compton suppression with gamma-ray spectrometry for 137Cs and 210Pb quantification. Natural matrix certified reference materials (CRM) were used for efficiency calibration and quality assurance.
Authors:S. Bürger, K. Mathew, P. Mason, and U. Narayanan
The characterized concentrations of 24 impurity elements in New Brunswick Laboratory (NBL) Certified Reference Material (CRM)
124 were reevaluated. A provisional certificate of analysis was issued in September 1983 based upon the “as prepared” values
(gravimetric mixing). The provisional certificate does not state uncertainties for the characterized values, or estimate the
degree of homogeneity. Since release of the provisional certificate of analysis various laboratories have reported analytical
results for CRM 124. Based upon the reported data a re-evaluation of the characterized values with an estimate of their uncertainties
was performed in this work. An assessment of the degree of homogeneity was included. The overall difference between the re-evaluated
values for the 24 impurity elements and the “as prepared” values from the provisional certificate of analysis is negligible
compared to the uncertainties. Therefore, NBL will establish the “as prepared” values as the certified values and use the
derived uncertainties from this work for the uncertainties of the certified values. The traceability of the “as prepared”
values was established by the gravimetric mixing procedure employed during the preparation of the CRM. NBL further recommends
a minimum sample size of 1 g of the CRM material to ensure homogeneity. Samples should be dried by heating up to 110 °C for
one hour before use.
Authors:D. Kelly, K. Mattson, K. Nielsen, R. Weir, and S. White
The analysis of antimony in soil is an important component in the assessment of environmental risk associated with the discharge
of munitions at small arms ranges. Proficiency testing samples associated with accreditation to the ISO 17025 standard have
been examined for their antimony content using Instrument Neutron Activation Analysis (INAA) and using microwave assisted
in situ hydrofluoric acid or nitric acid digestion, or nitrate ashing, followed by ICP-MS analysis. Data are compared with
the proficiency testing criteria associated with accreditation and with consensus data. All three techniques afford data which
are consistent with accredited analyses. However, the antimony concentrations obtained are method dependant, and generally
as follows; INAA > in situ HF > nitrate ashing > nitric acid. In situ HF data and nitrate ashing data are systematically higher
and lower than consensus values, respectively, but within the acceptable accreditation range. INAA is the only technique which
affords a concentration for antimony in the certified reference material PACS-2 (10.0 ± 0.1 μg g−1) which is not statistically different from its certified value (11.3 ± 1.3 μg g−1).
Authors:Yong Chung, Sun Kim, Gwang Sun, Jong Lim, Jong Moon, Kye Lee, and Hwa Yoo
The aim of the research is to find out better medicinal stuff for thyroid cancer patients who are required to have a low level
iodine diet. Iodine contents in 12 kinds of oriental herbal medicinal prescriptions, which are frequently used for thyroid
cancer patients, are determined using instrumental neutron activation analysis. The biological certified reference material
was used for analytical quality control. The relative errors and standard deviations for the iodine analysis were less than
2.88 and 18.5%, respectively. The level of iodine contents for four medicinal samples detected was in the range of about 3–210 mg/kg,
the concentrations of eight samples were estimated from the detection limit under the given analytical conditions. In addition,
the informative concentrations of 17 essential elements with special functions such as Al, As, Ba, Br, Ca, Cl, Cr, Fe, K,
Mg, Mn, Na, Rb, Sr, Ti, V, and Zn in the samples were also determined together with their detection limits for data inter-comparison.
The relative errors and standard deviations for these elements were in the range of 0.1–18.0%, and 2–20%, respectively.
Instrumental neutron activation analysis (INAA) was used to determine trace elemental contamination in bird feathers. Primary
feathers from twelve mallard (Anas platyrhynchos) ducks, migrating through the Thousand Islands region of Ontario, Canada, were analyzed for selenium, mercury, chromium,
arsenic and antimony. Certified reference materials were used to assess the quality of the analytical procedure. Quantification
of chemical elements was performed using Ortec Gamma Vision software. Five chemical elements were quantified, with corresponding
analytical uncertainties of less than 20%. Results indicated the presence of As (max = 0.13 mg kg−1), Cr (max = 2.6 mg kg−1), Hg (max = 7.7 mg kg−1), Sb (max = 0.31 mg kg−1) and Se (max = 1.31 mg kg−1). To assess the validity of using INAA as a quantitative analytical technique for feather samples, two standard reference
materials were examined and mercury results were compared to those obtained from both direct mercury analysis (DMA) and cold
vapour atomic absorption spectroscopy (CVAAS). Several CVAAS results differed significantly from the INAA results; in many
instances CVAAS appeared to under-report when compared to INAA, with relative percent difference values as high as 126%. Conversely,
results obtained using DMA compared favourably with INAA. For all samples, RPD values were within 30%. This is the first study
to use INAA to examine feather contamination in Canadian migratory waterfowl and the first to corroborate INAA feather results
by comparing them to those obtained using CVAAS and DMA.
Authors:H. Moreira, M. Vasconcellos, E. Alves, F. Santos, and M. Saiki
In Brazil, the use of herbal medicines is very popular due to its immense flora, cultural aspects and to the popular belief
that herbs, which are of natural origin, are safe and without undesirable side effects. Aside from that public interest in
natural therapies, the use of herbal medicines has increased expressively due to the high cost of synthetic medicines. In
this study, elemental compositions of herbal medicines from the species Ginseng, Ginkgo biloba, Centella asiatica, Mulberry and Aloe vera supplied by different suppliers were evaluated by neutron activation analysis. The concentrations of As, Ba, Br, Ca, Cl,
Co, Cr, Cs, Fe, Hf, K, Mg, Mn, Na, Rb, Sb, Sc, Th, Zn and some lanthanides were determined in these samples. Comparisons made
between the results indicated differences in their elemental contents depending on the plant species, origins of the samples
and the age of the leaves. The results also showed that the herbal medicines contain elements such as Ca, Co, K, Fe, Mg and
Zn known as essential to humans and for treatment and prevention of diseases. Toxic elements such as Hg, Cd and Cu were not
detected. Elements As and Sb were detected in some samples but at very low concentrations at the μg kg−1 levels. Herbal medicine results were also compared to literature values. Biological certified reference material was analyzed
for quality control of the analytical results.
During the author's 39 years with the National Bureau of Standards (NBS)/National Institute for Standards and Technology (NIST)
as an employee, and since then as Guest Researcher, he has been intimately involved with biological Standard Reference Material
(SRM) production and analyses. His involvement with biological reference materials started with the very first biological
certified reference material (CRM), the SRM 1571, Orchard Leaves, initiated in 1968 and issued in 1971, through the latest
material (SRM 1575a, Pine Needles - renewal), issued in 2003. In addition, for more than 20 years he was Technical Coordinator
for botanical SRMs for the NBS/NIST Analytical Chemistry Division. This paper contains his historical reflections and highlights
from those years, and includes the techniques used to obtain and process these materials, new developments and procedures
that resulted in vastly improved reference materials, the application of high accuracy neutron activation analysis to the
certification of these standards, and the trace element quality assurance vital to the accuracy of these standards.
36Cl is a beta-emitter with a very low specific activity. It is produced during the irradiation of nuclear fuel, in the reactor core of power plants, from neutron capture by stable 35Cl that may be present at trace level in any part of the irradiated material. Due to its long half-life (T1/2 = 3.01 . 105 y), 36Cl may be significant in impact assessment studies of disposal sites of nuclear wastes. Considering these different elements, the National Radioactive Waste Management Agency (Andra-France) requests information on the 36Cl content of the waste packages destined to be stored at Andra sites. As for other halogens, the measurement of 36Cl is a difficult analytical task in view of its potential losses during the different chemical steps and also because of the lack of international certified reference material needed to validate the chemical and measurement procedures. This paper describes the methodology processed to constitute an in-house solid reference sample with a known content of stable and radioactive chlorine. The original radiochemistry developed to extract 36Cl from solid samples and purify it before a liquid scintillation counting is explained. The comparison of the results given by this radiochemical protocol and other methods allow its validation. The replication of the measurements on the constituted reference materials gives a repeatability around 8% at a confidence level of 95% that is very close to the calculated combined uncertainty value.