Establishing adequate conditions for mercury determination in environmental samples by INAA
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2017
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60 YEARS OF IEA-R1: INTERNATIONAL WORKSHOP ON UTILIZATION OF RESEARCH REACTORS
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Resumo
Mercury (Hg) is a toxic element released into the environment by various atrophic
activities. Consequently, the improvement of analytical methods for Hg determination
in environmental samples is of great interest. Instumental Neutron Activation
Analysis (INAA) is considered an adequate technique to determine several elements.
However, Hg determination by INAA is often hampered by its volatility, which causes
losses. The aim of this study was to establish adequate conditions for Hg determination
in environmental samples by INAA. The following parameters were evaluated:
the irradiation time, polyethylene capsule or envelope for irradiation and spectral interferences
caused by other elements present in the samples. For the study, four
certified reference materials (CRMs) were analyzed: INCT M-4 CormTis Comorant
Tissue, IAEA-085 Methylmercury, Total Mercury and Other Trace Elements in Human
Hair, NRC DOLT-3 Dogfish liver certified reference material for trace metals
and BCR 186 Trace elements in lyophilized pig kidney. Aliquots of these materials
were irradiated together with Hg synthetic standard in the IEA-R1 nuclear research
reactor. The Hg synthetic standard was prepared by pipetting aliquots of Hg standard
solution and thioacetamide solution into filter paper sheets or into polyethylene
capsules. The thermal neutron flux utilized was about 4.6 1012 n cm2 s1 and
the irradiation times were of 1 and 8h. The gamma activities of the samples and
standard were measured using a Ge detector coupled to a digital spectrum analyzer.
Hg was identified by the photopeaks of 77.34 keV of 197Hg and 279.20 keV of 203Hg.
Results obtained in this study indicated that the Hg impurities present in polyethylene
envelopes are negligible. The gamma ray activities of Hg standards measured
for different decay times indicated that there is no Hg loss after irradiation. Results
obtained in the analysis of CRMs indicated that the adequate irradiation time is of
1h, since long irradiations of 8h indicated the increase of spectral interferences such
as 198Au, 75Se and 24Na. The quality control of Hg results, obtained in the CRMs
using 1h of irradiation, indicated good precision and accuracy with |Z score| < 2. The
experimental conditions established in this study were applied to tree bark samples.
Detection limits for Hg of these analyses were about 0.14 g g1 and 1.9 g g1,
for the photopeaks of 197Hg and 203Hg, respectively.
Como referenciar
PEREZ, C.; SANTOS, E.C.; SAIKI, M. Establishing adequate conditions for mercury determination in environmental samples by INAA. In: 60 YEARS OF IEA-R1: INTERNATIONAL WORKSHOP ON UTILIZATION OF RESEARCH REACTORS, November 28 - December 01, 2017, São Paulo, SP. Abstract... São Paulo, SP: Instituto de Pesquisas Energéticas e Nucleares, 2017. p. 23-23. Disponível em: http://repositorio.ipen.br/handle/123456789/28716. Acesso em: 30 Dec 2025.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.