Application of DPPH Assay for Assessment of Particulate Matter Reducing Properties
by
Maria Agostina Frezzini 1,*
, Federica Castellani 1, Nayma De Francesco 1, Martina Ristorini 2,3 and Silvia Canepari 1
Maria Agostina Frezzini 1,*, Federica Castellani 1, Nayma De Francesco 1, Martina Ristorini 2,3 and Silvia Canepari 1
1
Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy
2
Research Institute on Terrestrial Ecosystems, National Research Council, Via G. Marconi, 2, 05010 Porano, Italy
3
Department of Biosciences and Territory, University of Molise, Via Hertz, 86090 Pesche, Italy
*
Author to whom correspondence should be addressed.
Atmosphere 2019, 10(12), 816; https://doi.org/10.3390/atmos10120816
Received: 24 October 2019 / Revised: 12 December 2019 / Accepted: 13 December 2019 / Published: 16 December 2019
(This article belongs to the Special Issue Oxidative Potential of Atmospheric Aerosols)
Different acellular assays were developed to measure particulate matter’s (PM) oxidative potential (OP), a metric used to predict the ability of PM in generating oxidative stress in living organisms. However, there are still fundamental open issues regarding the complex redox equilibria among the involved species which could include reducing compounds. The aim of this study was the pilot application of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay to PM in order to evaluate the presence of reducing species. The assay, commonly applied to biological matrices, was adapted to PM and showed good analytical performances. It allowed the analysis of conventional 24 h airborne PM samples with suitable sensitivity and good repeatability of the measurements. The assay was applied to seven samples representing possible PM contributes (certified urban dust NIST1648a; brake dust; Saharan dust; coke dust; calcitic soil dust; incinerator dust; and diesel particulate matter certified material NIST1650b) and to PM2.5 field filters. The same samples were also analyzed for elements. Preliminary results indicated that the assay gave a linear response and that detectable amounts of reducing species were present in PM samples. The combined application of DPPH and conventional OP assays could then permit, in the future, to gain more knowledge about the reaction and/or competition between oxidative and reducing processes.
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Keywords:
oxidative potential; PM redox properties; 2,2-diphenyl-1-picrylhydrazyl antioxidant assay; air quality monitoring
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MDPI and ACS Style
Frezzini, M.A.; Castellani, F.; De Francesco, N.; Ristorini, M.; Canepari, S. Application of DPPH Assay for Assessment of Particulate Matter Reducing Properties. Atmosphere 2019, 10, 816.
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