EPFR samples available for research
Environmentally Persistent Free Radicals (EPFRs) are radical-particle systems present in airborne-particulate matter and other environmental solid samples. EPFRs, which are formed by reactions between transition metals and organic material, may affect respiratory and cardiac health.
Researchers in the LSU Superfund Research Center's Materials Core laboratory have developed a method to synthesize surrogate samples of EPFRs with controlled particle composition and precisely controlled radical concentration number (spins/gram of sample). Such samples can be used in laboratory studies of EPFRs.
Laboratory generated simple, s-EPFRs: The LSU Superfund Research Center can provide interested laboratories and research groups with surrogate samples for research purposes. Samples are based on a silica matrix with a single particle size of 0.2 microns and smaller. The table below provides a selection of transition metals and aromatic molecule precursor of the s-EPFR systems presently being synthesized.
Laboratory generated complex, c-EPFRs: EPFRs derived from catalytic combustion of 1-Methyl Naphthalene in presence of Anthracene and an additive, MCP (monochlorophenol) are abbreviated as complex, c- EPFRs. A new two stage combustion reactor was developed to generate c-EPFRs with a well-defined and controlled composition. Specifically, this reactor provides an accurate control over EPFRs concentration, while allowing for the addition of other pollutants specific to Superfund sites in the reaction feed and continuing to allow control of metal speciation and concentration. The samples with c-EPFRs in high and low (c-EPFR hi/lo) concentrations are available in a demand. Usually, EPFR hi and EPFR lo with the EPFRs concentration level at ~1x1018 and 1x1016 EPFRs/g, respectively is synthesized.
| Metal System | Radical half-lifetime* in air s-EPFRs | Precursors |
|---|---|---|
| Cu(+2/+1) | Few hours | 1,2-dichlorobenzene (except Fe) |
| Fe (+3/+2) | ~1-3 days | 2-monochlorophenol |
| Ni(+2/+1) | ~3-4 days | Hydroquinone (low radical concentration) |
| Zn(+2/+1) | ~2 months | Catechol (low radical concentration) |
| c-EPFRs | ||
|---|---|---|
| Catalyzed by Fe2O3 nanoparticles |
~ 145 days | 1-methyl naphthalene, anthracene, and additives |
* The half-life time of the radical is the time when the initial concentration reduces by half. A sample with extended half-life time of the radicals can be supplied in a vacuum.
Customer service: Materials Core chemists will address your technical questions and help you select the optimal EPFR samples for your application.
Contact Stephania Cormier for details or for more information.