Thallium-201 was obtained by irradiating natural mercury with protons from IPEN's CV-28 Cyclotron. The chemical separation process chosen to separate thallium from mercury was an extraction chromatography technique. It consists on the passage of aqueous solutions (mobile phase), containing the elements that will be separated, through a glass column packed with an inert powder (support) saturated with the extractant (stationary phase).
The radiopharmaceutical201TlCl(thallium-201 chloride) is used in nuclear medicine for myocardial visualization. The solution of201TlCl was prepared using201Tl obtained by irradiating a natural mercury target with protons from the CV-28 cyclotron installed at IPEN-CNEN/SP. This solution was subjected to different quality control processes required for its use in medicine. Some of these controls concerned the determination of the radionuclidic impurities:200Tl,202Tl and203Hg; the chemical identification of201Tl+; the hydrazine concentration, mercury contamination and the presence of phosphate. Furthermore. the biological distribution in Wistar rats and tests for sterility, pyrogenicity and toxicity were carried out. It was verified that the solution obtained was in the form of thallous chloride. This radiopharmaceutical gave good heart images in animals but due to the high levels of200Tl and202Tl its use in humans is not possible unless enriched202Hg is used as target in the irradiation.
Authors:L. Fernandes, Zs. Éhen, T. Moura, Cs. Novák, and J. Sztatisz
Thermoanalytical techniques, being rapid and un-expensive have been used for the investigation of the cyclodextrin inclusion
complexes for three decades. The conventional thermoanalytical techniques (TG and DTA/DSC) follow the thermal properties of
the uncomplexed compounds. Consequently, the inclusion complex formation as well as the liberation of the entrapped guest
cannot be followed. Monitoring the products of the thermal fragmentation of parent cyclodextrin and the included molecule(s),
applying TG-MS combined technique provides evidence concerning the inclusion complex formation, and besides, gives selective
signal to follow the decomposition of the cyclodextrin inclusion complexes. b-cyclodextrin inclusion complexes of Thymol and
Lippia sidoides Cham essential oil extract have been prepared and investigated using conventional and combined (TG-MS) thermoanalytical techniques.
The evolved gas analysis proved the inclusion complex formation between the host and guests. By the evaluation of the experimental
results the elaboration of the entrapped guests from the cyclodextrin cavity could be followed.
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:L. Wiikmann, M. Bacchi, E. Fernandes, and M. Saiki
This work presents a comparison of analytical results obtained for U, Th, K, and Fe in solid material from tailings pond, carried out within the CIPC's Tailings Management Program, with those achieved by instrumental neutron activation analysis. The validity of the techniques applied for dissolution and determination of elements in high silicate grade material, as the present case, can be assured by good agreement of the resulst.
Authors:L. Lara, E. Fernandes, H. Oliveira, M. Bacchi, and E. Ferraz
The interactive processes operating on the continental shelf adjacent to the river mouth control the amount and the characteristics of the Amazon discharge reaching the Atlantic Ocean. In this study, the distribution of trace elemental concentrations, with emphasis to the rare-earth elements, in sediment cores collected at several stations from the Amazon continental shelf during the falling water period was investigated by instrumental neutron activation analysis. Cores from the terrigenous and blue water zones have relatively uniform REE concentrations throughout the profile. Cerium anomalies for samples of the upper section of the eight stations are consistently positive and of high values (normally >2). Similar variation in the elemental concentration ratios between the seabed sediments and Amazon River suspended sediments was seen for stations located in the biogenic and blue water zones, with an enrichment for Ce, Sm, Fe, Th, and Sc and a depletion for the La, Eu, Tb, Yb, Co, Cr, Cs, Hf, Ta, and Zn. The shale-normalized REE patterns from shelf sediments are enriched in LREE relative to HREE, with enrichment factors varying from 1.5 for stations near the river mouth (terrigenous zone) to 1.9 for stations located far in the blue water zone. Published data for the Amazon River suspended sediment agree remarkably well with this observation of LREE-enrichment.
Authors:H. Polli, L. Pontes, A. Araujo, Joana Barros, and V. Fernandes
The degradation kinetics of the ABS terpolymer (acrylonitrile-butadiene-styrene) was investigated by means of thermogravimetric
analysis. The samples were heated from 30 to 900°C in nitrogen atmosphere applying three different heating rates: 5, 10 and
20°C min−1. The Vyazovkin model-free kinetic method was used to calculate the activation energy (E) of the degradation process as a function of conversion and temperature. Between 20 and 80% of conversion, E was calculated
and the figures were: for ABS GP, E is 204.5±11.5 kJ mol−1 (medium value); for ABS HI, E is 239.0±9.8 kJ mol−1; for ABS HH, E is 242.4±5.4 kJ mol−1.
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:M. Bacchi, E. De Nadai Fernandes, S. Tsai, and L. Santos
The elemental composition of potato tubers from four varieties growing in an experimental field under conventional and organic
conditions was investigated. Br, Co, K, Na, Rb and Zn, determined by k0-instrumental neutron activation analysis, were used to distinguish the tubers according to the cultivation system. The difference
between organic and conventional potatoes was evidenced by cluster analysis, specially using Br, Co, K and Rb.
Authors:A. Souza, H. Danta, M. Silva, I. Santos, V. Fernandes, F. Sinfrônio, L. Teixeira, and Cs. Novák
The biodiesel obtained by transesterification by reaction between ester and an alcohol in the presence of catalyst. The purpose
of this work is to evaluate the thermal and kinetic behavior of the methanol biodiesel derived from cotton oil. The quality
analysis was done by gas chromatography and proton nuclear magnetic resonance spectrometry (1H NMR) in order to examine if the product meets with the requirements of the European Standard EN 1403. The thermogravimetric
profile of the cotton biodiesel indicated that the decomposition steps are associated to the volatilization and/or decomposition
of the methyl esters. Kinetic data was also obtained by thermal analysis.