Authors:L. Santos, E. De Nadai Fernandes, F. Tagliaferro, and M. Bacchi
Aiming at the determination of toxic and essential elements in Brazilian commercial bovine milk, 25 ultra high temperature
(UHT) milk samples were acquired in the local market of Piracicaba, SP. The samples were freeze-dried and analyzed by instrumental
neutron activation analysis (INAA) allowing the determination of Br, Ca, Co, Cs, Fe, K, Na, Rb and Zn. When the results were
expressed as concentration (mg·l−1) no significant differences were found. However, considering the dry matter, results showed a clear difference between the
mass fractions (mg·kg−1 d.w.) of skim milk and whole milk for the elements Br, Ca, K, Na, Rb and Zn, indicating that the removal of fat caused a
concentration effect in the dry matter of skim milks. Discrepancies were found between the concentrations of Ca and Na measured
by INAA and the values informed in the labels. Ca showed variations within 30% for most samples, while concentrations of Na
were up to 190% higher than informed values. The sample preparation and the INAA procedure were appropriate for the determination
of Br, Ca, Co, Cs, Fe, K, Na, Rb and Zn in milk samples.
Authors:F. Tagliaferro, E. De Nadai Fernandes, P. Bode, and H. Baas
The degree of homogeneity is normally assessed by the variability of the results of independent analyses of several (e.g.,
15) normal-scale replicates. Large sample instrumental neutron activation analysis (LS-INAA) with a collimated Ge detector
allows inspecting the degree of homogeneity of the initial batch material, using a kilogram-size sample. The test is based
on the spatial distributions of induced radioactivity. Such test was applied to samples of Brazilian whole (green) coffee
beans (Coffea arabica and Coffea canephora) of approximately 1 kg in the frame of development of a coffee reference material. Results indicated that the material do
not contain significant element composition inhomogeneities between batches of approximately 30–50 g, masses typically forming
the starting base of a reference material.
Authors:L. Santos, E. De Nadai Fernandes, M. Bacchi, and F. Tagliaferro
This study investigated the representativeness of samples for assessing chemical elements in milk bulk tanks. Milk samples
were collected from a closed tank in a dairy plant and from an open top tank in a dairy farm. Samples were analyzed for chemical
elements by instrumental neutron activation analysis (INAA). For both experiments, Br, Ca, Cs, K, Na, Rb and Zn did not present
significant differences between samples thereby indicating the appropriateness of the sampling procedure adopted to evaluate
the analytes of interest.
Authors:C. Elias, E. Fernandes, E. França, M. Bacchi, and F. Tagliaferro
Epiphytic bromeliads have been used as biomonitors of air pollution since they have specialized structures in leaves for absorbing
humidity and nutrients available in the atmosphere. Leaves of five bromeliad species were collected in the conservation unit
Parque Estadual Ilha do Cardoso, São Paulo State, Brazil, and analyzed by INAA. Vriesea carinata was the species showing most accumulation, with the highest mass fractions of K, Na, Rb and Zn. Similar results were previously
found for the same species collected in the dense ombrophilous forest. Chemical composition of bromeliads provided an indication
of the atmosphere status in the conservation unit.
Authors:C. Elias, E. Fernandes, E. França, M. Bacchi, and F. Tagliaferro
Resuspended soil and other airborne particles adhered to the leaf surface affect the chemical composition of the plant. A
well-defined cleaning procedure is necessary to avoid this problem, providing a correct assessment of the inherent chemical
composition of bromeliads. To evaluate the influence of a washing procedure, INAA was applied for determining chemical elements
in the leaves of bromeliads from Vriesea carinata species, both non-washed and washed with Alconox, EDTA and bi-distilled water. Br, Ce, Hg, La, Sc, Se, Sm and Th showed higher
mass fractions in non-washed leaves. The washing procedure removed the exogenous material without leaching chemical elements
from inside the tissues.
Authors:H. Oliveira, E. Fernandes, M. Bacchi, G. Sarriés, and F. Tagliaferro
Inorganic components were surveyed of some Brazilian cigarette tobacco by INAA. Sixteen different brands were taken from the consumer market and analyzed for As, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, K, La, Na, Rb, Sc, Sm, Sr and Zn elements. Comparisons between the results from this work and those originated from several cigarette tobacco producing countries, indicate significant variation in the levels of some elements.
Authors:E.A.N. Fernandes, F.S. Tagliaferro, P. Bode, M.A. Bacchi, and G.A. Sarriés
In a preliminary study performed with the waste rocks from the future uranium mine to be explored in Brazil, 106 samples were taken from the eight main lithologies found in the massif and analysed by instrumental neutron activation analysis (INAA) for 20 elements. For samples from the same lithology, a high variability in the concentration of most of the elements was found (coefficient of variation larger than 20%), which might be attributed to either insufficient homogenisation of minerals or to local variation within lithology. The hypothesis that the variability within the lithology does not have an influence to the total variability was tested by analysing 5 replicates of the 5 most contrasting samples from the predominant lithology (plagioclase-microcline-gneiss), chosen after applying statistical evaluation (principal components and cluster analyses). Results indicated that homogenisation of samples was adequate due to low variation among replicates. The hypothesis tested was rejected with a confidence level higher than 99% for all the elements, corroborating the large intra-lithology variability.
Authors:F. S. Tagliaferro, E. A. De Nadai Fernandes, and M. A. Bacchi
A random sampling was carried out in the coffee beans collected for the preparation of the organic green coffee reference
material in view of assessing the homogeneity and the presence of soil as impurity. Fifteen samples were taken for the between-sample
homogeneity evaluation. One of the samples was selected and 10 test portions withdrawn for the within-sample homogeneity evaluation.
Br, Ca, Co, Cs, Fe, K, Na, Rb, Sc and Zn were determined by instrumental neutron activation analysis (INAA). The F-test demonstrated that the material is homogeneous for Ca, Co, Cs, K and Sc, but not homogeneous for Br, Fe, Na, Rb and Zn.
Results of terrigenous elements suggested negligible soil contamination in the raw material.
Authors:I. M. H. Lima, M. N. Frota, E. A. N. Fernandes, P. Bode, and F. S. Tagliaferro
This paper describes an analytical method using a nuclear-related technique for the detection of forbidden doping substances
in the urine of race horses. The proposed method, adapted from the Méthode Alcaline Sur C-18 developed by the French Laboratoire
de Contrôle Antidopage, is based on gas chromatography separation followed by mass spectrometry (GC-MS). The method was validated
for caffeine, identified as the most frequent doping substance in the Brazilian horseracing activity. This validation is also
a major requirement to achieve ISO/IEC 17025 laboratory accreditation. The validation has led to several metrological challenges
because the decisions are largely based on qualitative results (“false-positive” and/or “false-negative”) and the degree of
accuracy, as well as the traceability had to be determined in the absence of certified matrix reference materials.
Authors:M. Bacchi, L. Santos, E. De Nadai Fernandes, P. Bode, F. Tagliaferro, and E. França
The effectiveness of a Compton suppression system (CSS) for instrumental neutron activation analysis of plant materials was
evaluated. Suppression factors were measured with 137Cs sources. Five certified reference materials were analyzed and the detection limits calculated from both suppressed and
unsuppressed spectra were compared. The CSS demonstrated to be useful for lowering the detection limits of ten out of sixteen
elements tested, showing a maximum improvement factor of 3.9. The system performance was strongly influenced by the sample
composition and also by the measurement conditions, indicating the importance of testing each individual sample type and analytical