 |
| Titel |
A semi-automated system for quantifying the oxidative potential of ambient particles in aqueous extracts using the dithiothreitol (DTT) assay: results from the Southeastern Center for Air Pollution and Epidemiology (SCAPE) |
| VerfasserIn |
T. Fang, V. Verma, H. Guo, L. E. King, E. S. Edgerton, R. J. Weber |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1867-1381
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 8, no. 1 ; Nr. 8, no. 1 (2015-01-29), S.471-482 |
| Datensatznummer |
250116068
|
| Publikation (Nr.) |
 copernicus.org/amt-8-471-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| A variety of methods are used to measure the capability of particulate matter
(PM) to catalytically generate reactive oxygen species (ROS) in vivo, also
defined as the aerosol oxidative potential. A widely used measure of aerosol
oxidative potential is the dithiothreitol (DTT) assay, which monitors the
depletion of DTT (a surrogate for cellular antioxidants) as catalyzed by the
redox-active species in PM. However, a major constraint in the routine use of
the DTT assay for integrating it with large-scale health studies is its
labor-intensive and time-consuming protocol. To specifically address this
concern, we have developed a semi-automated system for quantifying the
oxidative potential of aerosol liquid extracts using the DTT assay. The
system, capable of unattended analysis at one sample per hour, has a high
analytical precision (coefficient of variation of 15% for positive
control, 4% for ambient samples) and reasonably low limit of detection
(0.31 nmol min−1). Comparison of the automated approach with the
manual method conducted on ambient samples yielded good agreement
(slope = 1.08 ± 0.12, r2 = 0.92, N = 9). The system
was utilized for the Southeastern Center for Air Pollution & Epidemiology
(SCAPE) to generate an extensive data set on DTT activity of ambient
particles collected from contrasting environments (urban, roadside, and
rural) in the southeastern US. We find that water-soluble PM2.5 DTT
activity on a per-air-volume basis was spatially uniform and often well
correlated with PM2.5 mass (r = 0.49 to 0.88), suggesting regional
sources contributing to the PM oxidative potential in the southeastern US.
The correlation may also suggest a mechanistic explanation (oxidative stress) for observed PM2.5
mass-health associations. The heterogeneity in the intrinsic DTT activity (per-PM-mass basis)
across seasons indicates variability in the DTT activity associated with
aerosols from sources that vary with season. Although developed for the DTT
assay, the instrument can also be used to determine oxidative potential with
other acellular assays. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|