Total determination and direct chemical speciation of Hg in fish by solid sampling GF AAS

Author(s)

Naozuka, Juliana ^[1] ; Nomura, Cassiana Seimi ^[2]

Affiliation

^[1] Univ Fed Sao Paulo, BR-09972270 Diadema, SP - Brazil

^[2] Univ Sao Paulo, Inst Quim, Dept Quim, BR-05513970 Sao Paulo - Brazil

• Document type: Journal article
• Source: Journal of Analytical Atomic Spectrometry; v. 26, n. 11, p. 2257-2262, 2011.
• Web of Science Citations: 11

Abstract

Simple and rapid analytical procedures for the direct determination of total Hg and for direct chemical speciation of Hg(2+) and methylmercury (MHg) in fish were proposed after careful optimization of the heating program and the addition of appropriate chemical modifiers by solid sampling graphite furnace atomic absorption spectrometry (SS-GF AAS). The total determination was done using Ir film and 5 mu g Pd + 3 mu g Mg solution as permanent and co-injected chemical modifiers, respectively. For direct chemical speciation, 5 mu g Pd + 3 mu g Mg or 5 mu g Pd + 3 mu g Mg + 0.5% w/v Triton X-100 solutions were used as co-injected chemical modifiers. The accuracy of both procedures was verified using the certified reference material (CRM) of tuna fish (CE-464), lobster hepatopancreas (TORT-2) and dogfish (DOLT-2). The certified and the found concentrations were statistically concordant (Student's t-test). The total Hg concentration in the tuna fish candidate reference material produced in our laboratory was 2.66 +/- 0.15 mg kg(-1). In the sample ground in a cryogenic mill, the Hg(2+) concentrations were 0.553 and 0.559 mg kg(-1) and by the difference between the total Hg and Hg(2+) concentration was obtained the MHg concentration, 5.11 and 4.73 g kg(-1), using Pd + Mg and Pd + Mg + Triton respectively. These results reveal a high concentration of the methylated species that it is most toxic Hg species. (AU)