Production of fish reference material for Hg and MeHg determination

• Grant number: 09/18525-7
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: March 01, 2010
• End date: August 31, 2012
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Analytical Chemistry
• Principal Investigator: Cassiana Seimi Nomura
• Grantee: Rodrigo Chelegão
• Host Institution: Centro de Ciências Naturais e Humanas (CCNH). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil

Abstract

Mercury (Hg) and methylmercury (MeHg) are toxic compound that have to be monitored in a environmental system. Fishes, due to their capacity in storing these compounds in their tissues, are commonly used as sentinel organism in the environmental risks investigation acting as indicators of contamination. The determination of Hg in complex matrices such as fish tissues can be done by several analytical techniques. Besides this kind of analysis is performed frequently, the emission of wrong results is not uncommon. An import key to guarantee the quality of analytical results is the use reference materials (RM) for the method calibration and accuracy evaluation. Many RM of fish containing defined concentration of total Hg is available. However, it is known that the study about chemical species investigation has becoming common, because this kind of study give us information about analyte toxicity and essentiality. In the case of Hg, it is known, MeHg is the most toxic form of Hg. The lack of RMs for chemical species becomes important the production of new materials for quality control. In this way, the aim of this work is the production of RM of fish tissue to be applied in Hg and MeHg determination. One of the most important step in the production of RM for chemical species is the sample preparation that should avoid contamination, analyte loss and species interconvertion. Two procedure of sample preparation will be evaluated: freeze-drying and freezing of raw material. Other parameters that will be investigated are the sample homogeneity and micro homogeneity, the minimum sample mass size, particle segregation and particle size. Cold vapor atomic absorption spectrometry (CV AAS) and graphite furnace atomic absorption spectrometry (GF AAS) are the main method used in this study. For intercalibration process, we will contact researchers of other institutions, such as CCNH/UFABC, IQ/USP, CENA/USP, CETESB, EMBRAPA/São Carlos, DQ/UFSCar, DQ/UFSM, among others. (AU)