Determination of residual manganese in Mn porphyrin-based superoxide dismutase (SOD) and peroxynitrite reductase mimics.

Journal Article (Journal Article)

The awareness of the beneficial effects of Mn porphyrin-based superoxide dismutase (SOD) mimics and peroxynitrite scavengers on decreasing oxidative stress injuries has increased the use of these compounds as mechanistic probes and potential therapeutics. Simple Mn2+ salts, however, have SOD-like activity in their own right both in vitro and in vivo. Thus, quantification/removal of residual Mn2+ species in Mn-based therapeutics is critical to an unambiguous interpretation of biological data. Herein we report a simple, sensitive, and specific method to determine residual Mn2+ in Mn porphyrin preparations that combines a hydrometallurgical approach for separation/speciation of metal compounds with a spectrophotometric strategy for Mn determination. The method requires only common chemicals and a spectrophotometer and is based on the extraction of residual Mn2+ by bis(2-ethylhexyl)hydrogenphosphate (D2EHPA) into kerosene, re-extraction into acid, and neutralization followed by UV-vis determination of the Mn2+ levels via a Cd2+-catalyzed metallation of the H2TCPP4- porphyrin indicator. The overall procedure is simple, sensitive, specific, and amenable to adaptation. This quantification method has been routinely used by us for a large variety of water-soluble porphyrins.

Full Text

Duke Authors

Cited Authors

  • Rebouças, JS; Kos, I; Vujasković, Z; Batinić-Haberle, I

Published Date

  • December 5, 2009

Published In

Volume / Issue

  • 50 / 5

Start / End Page

  • 1088 - 1091

PubMed ID

  • 19660888

Pubmed Central ID

  • PMC2752483

Electronic International Standard Serial Number (EISSN)

  • 1873-264X

Digital Object Identifier (DOI)

  • 10.1016/j.jpba.2009.07.002


  • eng

Conference Location

  • England