**7. References**

Adams PC, Bradley C, Frei JV. Hepatic zinc in hemochromatosis. Clin Invest Med.1991;14:16-20.

Fresh tissue is not always available for chemical analysis, but formalin-fixed tissue often is. In our study, zinc concentration measurements in fresh liver tissue and deparaffinized tissue have been shown to be concordant. We have found in fresh e deparaffinized tissues respectively, 173,6 ± 37,9 µg/g dry weight and 220,2 ± 127 µg/g dry weight. Two deparaffinized tissue samples showed higher values of zinc than the others samples, causing a higher standard deviation. There was no evidence of mineral contamination

We found only one study in the literature, conducted at the Mayo Clinic by Bush et al. (1995) that compared zinc concentration in fresh and deparaffinized liver tissue. Their study investigated the concentration of metals in several organs using material obtained from autopsy of 30 presumably healthy individuals. Zinc concentration found in fresh liver tissue was 191 ± 56.3 µg/g dry weight, and, in formalin-fixed tissue, 204 ± 63.2 µg/g dry weight. They concluded that formalin fixation long-term storage has little effect on zinc

Due to the clinical importance of zinc in liver diseases, the use of paraffin-embedded specimens for analysis is extremely useful when fresh tissue is not available. Stored material for analysis may be available even years after the biopsy or autopsy sample was obtained.

More than the results themselves, the proposed protocol for paraffinization/deparaffinization as well as for sample preparation for zinc determination by atomic spectroscopy in paraffinized samples were adequately established. According to the results of this study, paraffin embedding and deparaffinization do not significantly affect the determination of zinc

ANVISA – Agência Nacional de Vigilância Sanitária (Sanitary Surveillance National

ICH – International Conference on Harmonisation of Technical Requirements for

We are grateful to Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Fundo de

Adams PC, Bradley C, Frei JV. Hepatic zinc in hemochromatosis. Clin Invest

Incentivo a Pesquisas – Hospital de Clínicas de Porto Alegre (FIPE-HCPA).

concentrations in liver tissue, and, therefore, stored material can be used for analysis.

during the embedding process to account for these divergent values.

**4.1 Conclusion** 

**5. Glossary** 

Agency).

AAS – Atomic Absorption Spectrophotometry.

Registration of Pharmaceuticals for Human Use.

FDA – Food and Drug Administration.

Med.1991;14:16-20.

**6. Acknowledgements** 

**7. References** 

concentrations in tissue and that zinc was homogeneously distributed in liver.


**Section 2** 

**UV-VIS Spectroscopy** 


http://www.fda.gov/CDER/GUIDANCE/4252fnl.htm. Accessed: June 30, 2011.

Wortmann AC, Froehlich PE, Pinto RB, et al. Hepatic iron quantification by atomic absorption spectrophotometry: Full validation of an analytical method using a fast sample preparation. Spectroscopy 2007; 21:161-167.
