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A persistent hexabromonaphthalene isomer is 2,3,4,5,6,7-hexabromonaphthalene
Journal of Toxicology and Environmental Health
|January 1, 1985
Summary
This study identifies a minor isomer of hexabromonaphthalenes (HBNs), 2,3,4,5,6,7-HBN, using NMR spectroscopy. This persistent environmental contaminant can be detected in rat liver tissue long after exposure.
Area of Science:
- Environmental Chemistry
- Organic Chemistry
- Toxicology
Background:
- Polybrominated biphenyl (PBB) mixtures often contain brominated naphthalenes as synthesis byproducts.
- Hexabromonaphthalenes (HBNs) are produced as a mixture of isomers during naphthalene bromination.
Purpose of the Study:
- To definitively identify the minor isomer of HBNs formed during synthesis.
- To characterize the persistence and detectability of this HBN isomer in biological tissues.
Main Methods:
- High-field nuclear magnetic resonance (NMR) spectroscopy was employed for structural elucidation.
- Brominated [1-13C]naphthalene was used as a precursor for isomer synthesis and analysis.
- A combination of solvent extraction, partition, and adsorption chromatography was utilized for isolation.
Main Results:
- The minor HBN isomer was definitively identified as 2,3,4,5,6,7-HBN.
- This isomer exhibits extreme persistence in biological systems.
- 2,3,4,5,6,7-HBN was isolated from rat liver 10 days post-exposure to the HBN mixture.
Conclusions:
- The minor isomer 2,3,4,5,6,7-HBN is a significant component of synthesized HBN mixtures.
- The extreme persistence of 2,3,4,5,6,7-HBN raises concerns about its bioaccumulation and long-term environmental impact.