IJUP08 - Universidade do Porto

Optimization Study for Arsenic Quantification in Fish Using
Microwave-assisted Digestion and Graphite Furnace Atomic
Absorption Spectrometry
Ana C. Silva 1,2 , S. Morais 1,* , A. Novo 1 , C. Luz 1 , E. Pinho 2 , S. Conceição 2 , C. Delerue-
Matos 1 and M.B.P.P. Oliveira 2
1 REQUIMTE/Instituto Superior de Engenharia do Porto, Rua Dr. António Bernardino de Almeida
431, 4200-072 Porto, Portugal.
2 REQUIMTE/Serviço de Bromatologia, Faculdade de Farmácia da Universidade do Porto, Rua
Aníbal Cunha, 164, 4099-030 Porto, Portugal.
*e-mail: sbm@isep.ipp.pt
Heavy metals from anthropogenic sources are increasingly being released into seawater,
tend to accumulate in the biota and are subsequently transferred to humans through the
food chain. It has been shown that water metals levels are positively correlated with
concentrations in fish tissues [1]. Portugal is the biggest consumer of fish among all the
European Union countries and one of the biggest in the world. Arsenic is toxic to human
health even in trace amounts and the provisional tolerable weekly intake (PTWI) is 15
μg/kg of body weight per week [2].
The aim of this work is to develop an accurate and precise methodology based on closed
vessel microwave-assisted digestion coupled with graphite furnace atomic absorption
spectrometry (GFAAS) with Zeeman effect background correction for total arsenic
determination in dry edible parts of fishes. In order to obtain the complete decomposition
of the sample, the influence of sample weight, the oxidizing agents, temperature, pressure
and time of digestion were optimised. Concerning the quantification of arsenic by GFAAS,
the interferences were effectively eliminated by using Pd(NO3)2 as matrix modifier and by
optimising the graphite furnace operating pyrolysis and atomization temperatures. Also,
several quantifications methods were tested and compared.
Acknowledgments
The authors thank the Universidade do Porto for the financial support through the programme
Investigação Científica na pré-graduação-Proj. Pluridisciplinares – Concurso 2007.
References:
[1] Has-Schön, E., Bogut. I and Strelec, I. (2006), Heavy metal profile in five species included in
human diet, domiciled in the end of flow river Neretva (Croatia), Environmental Contamination
Toxicology, 50, 545-551.
[2] Alinnor, I.J. (2005), Assessment of elemental contaminants in water and fish samples from Aba
river, Environmental Monitoring and Assessment, 102, 15-25.
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