Methodology

Evaluating the use of 3'-(p-Aminophenyl) fluorescein for determining the formation of highly reactive oxygen species in particle suspensions

Corey A Cohn^1,2,5 , Christopher E Pedigo³ , Shavonne N Hylton² , Sanford R Simon⁴ and Martin AA Schoonen^1,2

¹  Center for Environmental Molecular Science, Stony Brook University, Stony Brook, NY 11794-2100, USA

²  Department of Geosciences, Stony Brook University, Stony Brook, NY 11794-2100, USA

³  Department of Biological Sciences, Stony Brook University, Stony Brook, NY 11794, USA

⁴  Department of Pathology, Stony Brook University Hospital, Stony Brook, NY 11794, USA

⁵  National Research Centre for the Working Environment, Lerso Parkalle 105, 2100 Copenhagen, Denmark

author email corresponding author email

Geochemical Transactions 2009, 10:8doi:10.1186/1467-4866-10-8

Published:	11 August 2009

Abstract

Background

Given the importance of highly reactive oxygen species (hROS) as reactants in a wide range of biological, photochemical, and environmental systems there is an interest in detection and quantification of these species. The extreme reactivity of the hROS, which includes hydroxyl radicals, presents an analytical challenge. 3'-(p-Aminophenyl) fluorescein (APF) is a relatively new probe used for measuring hROS. Here, we further evaluate the use of APF as a method for the detection of hydroxyl radicals in particle suspensions.

Results

Particle-generated hROS can be quantified with an estimated detection limit of 50 nM. Measurements of hROS in two National Institute of Standards and Technology (NIST 2709 and 2710) soil suspensions and a pyrite suspension show non-linear particle dose-response curves for hROS generation. APF can also be used in solutions containing no dissolved molecular oxygen (O₂) to determine the role of O₂ in the formation of hROS. Results confirm that O₂ is mechanistically important in the formation of hROS by dissolved ferrous iron and in pyrite suspensions.

Conclusion

Given the non-linear dose-response curves for particle generation of hROS, we recommend using several particle loadings in experiments aimed to compare particles for their hROS generation potential. The method presented here is specific to hROS and simple to perform. The analysis can be conducted in mobile labs as only basic laboratory equipment is required.